The Real Estate Institute of Victoria has urged the Allan government to cut stamp duty and consider introducing tax incentives for long-term rental properties.

Housing crisis: Victoria ‘overly reliant’ on stamp duty, REIV warns Allan Labor government

While abatement requests were down citywide, they were up in the core of downtown, where office towers help power the city’s tax base, and thus its $4.28 billion operating budget.

As office market slump continues, more downtown property owners are seeking tax breaks - The Boston Globe

Editor&#x27;s note: Because of technical issues, the Recorder of Deeds had been unable to send an accurate Deeds listing. This post shows deeds from the backlog as a result of

3 Manheim Township properties sold for over $1 million [Deeds recorded: Feb. 19, 2024] | Deeds Records in Lancaster County | lancasteronline.com

Property inspections are underway in the city of St. Joseph.This is according to a city code enforcement officer who spoke to our reporting partners at WSJM.She

More than 500 property inspections planned in St. Joseph

The owners of a Hollywood Hills mansion were shocked to find their mansion, which recently hit the market, was being occupied by a group of squatters who used it to host large parties and even rent it to OnlyFans models.

Squatters turn Hollywood Hills mansion into party house; rent property to OnlyFans models - CBS Los Angeles

Propty

propty

Here is a definition of data type, commonly referred as type: > A data type is a classification of the type of data that a variable or object can hold in computer programming. Most programming languages I encountered in school were strictly typed. Meaning that if you defined that variable as type string, it will be a string and nothing else. Unlike Javascript where you don’t have to decide if a variable should be a boolean or a string, you can just change it at any time, or the interpreter will do so for you (see lightning talk ) WAT If you think about it, when you create a variable and call it isRed you sort of made a binding contract with yourself that it will return a boolean. So if you created that variable in a strictly types language you would say boolean isRed at it’s definition, and if isRed is not a boolean then your program will warn you, yell at you, or simply give up. Let’s be clear, we make mistakes, so types help us make less of them. Now, you say — get to the point, the title said PropTypes!!! This is the point — I am not terribly happy with Flow, in my opinion just go with TypeScript if you are going to go through the trouble. BUT — if you are working on a bigger project, or in teams, the minimal amount of effort you can put in avoiding type kind of mistakes/errors is to use PropTypes. Because if I want to use the component Sidebar, we can look at the prop types which are `logo: string.isRequired; links: object; footer: instaceOf(Footer)` At least to me this is enough for me to use the component without reading how it really works. It’s kind of like a small wiki for that component. We use Ruby on the backend and in our model files we have comments of what the database table looks like. I think it is a working contract we have on our team to keep those comments up to date, and I think that is what prop types are as well. Sometimes they will just make a lot of unnecessary noise, but if they save you from one big bug — to me that is worth it. Here are some resources if you would like to learn more about things I talked about in this article: Prop Types npm package (a static typechecker for JS) Flow TypeScript

A Case for PropTypes

Photo by on chuttersnap Unsplash In the we learned about the differences between and and how to use them in your React/React Native application. previous article props state In this article, we will dive into . PropTypes When you write a large application, data validation plays a pivotal role. React supports data validation through . It is React’s in-built type-checker. PropTypes Props in a component can be type-checked using PropTypes. Do I really need to define PropTypes? You can define components without . But, without or some form of type checking, we run into the risk of passing in a wrong data type to a component, which could cause a crash or some unexpected behavior in your application. PropTypes PropTypes I highly recommend using in your react native components, to avoid unexpected glitches to the user. PropTypes Defining PropTypes for a component Let’s take a look at the example below. The component ‘ ’ has a set of defined . MyComponent PropTypes The props here are defined with their respective for type-checking. PropTypes There are different types of validators in the above example (string, array, func, number, bool and so on..). This enables you to declare that a is a specific Javascript type. prop Anyone using this component will now know all the and the respective types required by it. React would throw an error on the console, when an incorrect datatype is passed to the component. This will enable us to catch errors during development time. props isRequired — Is this required? In our example, all the are required for the component . By default the for a component are optional. By adding the keyword, we are making sure a warning is generated if the is not provided to the component. props MyComponent props isRequired prop It is always safe to use the for props in the component to make sure we are not missing any that are needed by the component. isRequired props When you start coding a component, it is always easy to mark all the props as required. This helps in handling null cases in your code, and also makes sure that you do not forget to pass in the to the component. props If you do not use , then the other option would be to set default values to your props. isRequired When you miss passing a required to the component, a warning is generated like below. This ensures that the developer does not miss any required to the component. prop props Sample warning generated by react on missing a required prop. What are defaultProps ? Default values can be assigned to the props using . When a component does not receive it’s props, then it resorts to the that has been assigned. defaultProps defaultProps In the above code snippet you can see all the default values that have been assigned to the props for . It is not necessary to assign defaultProps if you have marked your props as required. MyComponent Tip: Always define explicit defaultProps for all optional props. It is interesting to note that the type-checking using happens after the are assigned. So it type checks the default values assigned to the props as well. Neat! PropTypes defaultProps Next time you code a component, make sure to add your type-checking using React’s PropTypes. This article was originally published at and http://adhithiravichandran.com/ https://codeburst.io/ If you liked this article, follow me for more tutorials and articles on React Native and ReactJs.

Are you using PropTypes in React Native?

It's becoming increasingly difficult to choose the correct technology for a new app or website. React is one of the most rapidly expanding Javascript frameworks. There has been a steady rise in demand for React certification as JavaScript technologies have established themselves in the industry. React is a clear winner for front-end developers all around the world because of its short learning curve, reusable components, and clean abstraction. To help you with your interview preparation, we've compiled a list of some of the most common React interview questions and answers. Let's take a look at five of the most common React Interview questions: 1. What are React's features? JSX: JSX is a JavaScript syntactic extension. It's a term used in React to define the desired appearance of the user interface. It is possible to write HTML structures in the same file as JavaScript code thanks to the JSX language extension. : There are many components in a single React application, so it's important to know what they are and how they work together. It separates the user interface into components that may be reused and processed independently of one another. Components : In React, the virtual DOM is a lightweight replica of the actual DOM that is stored in memory. Rather to updating every item in the DOM, the virtual DOM simply updates one object at a time. Virtual DOM : In React, the one- way data binding ensures that everything is modular and quick. A React app's unidirectional data flow necessitates nesting child components inside parent components. One-way data-binding : In order to keep things running smoothly, React only updates the parts that have changed. As a consequence, web applications run substantially more quickly. High Performance 2. What are the major differences between Real DOM and Virtual DOM? (Real Dom vs Virtual DOM) Real DOM Virtual DOM It's taking a while to update. It's more responsive in terms of updating. It is possible to make HTML changes straight from the command line. It is not possible to change HTML directly. If an element's data changes, a new DOM is created. If an element changes, the JSX is updated. In order to manipulate the DOM, the process is quite time-consuming. It's fairly simple to work with the DOM. Memory is being squandered. Memory is not wasted. 3. How is React's ES6 syntax different from that of ES5 in terms of syntax? When comparing ES5 to ES6, the following features of the syntax have been updated: importing vs. requiring export vs exports component and function props state Import vs. Requiring ES5 var React = require('react'); ES6 import React from 'react'; Export vs Exports ES5 module.exports = Component; ES6 export default Component; Component and Function // ES5 Component
var MyComponent = React.createClass({
  render: function () {
    return <h3>Hello Edureka!</h3>;
  },
})
// ES6 Function
class MyComponent extends React.Component {
  render() {
    return <h3>Hello Edureka!</h3>
  }
} Props // ES5
var App = React.createClass({
  propTypes: { name: React.PropTypes.string },
  render: function () {
    return <h3>Hello, {this.props.name}!</h3>
  },
})
// ES6
class App extends React.Component {
  render() {
    return <h3>Hello, {this.props.name}!</h3>
  }
} State // ES5
var App = React.createClass({
  getInitialState: function () {
    return { name: 'world' }
  },
  render: function () {
    return <h3>Hello, {this.state.name}!</h3>
  },
})
// ES6
class App extends React.Component {
  constructor() {
    super()
    this.state = { name: 'world' }
  }
  render() {
    return <h3>Hello, {this.state.name}!</h3>
  }
} 4. List some of the most important benefits of using React in your essay. React has a number of significant benefits, including the following: It improves the speed and responsiveness of the program. It is suitable for both the client and the server. The readability of code has improved as a result of JSX With React, additional frameworks like Meteor and Angular may be easily integrated. Writing UI test cases becomes a breeze with the help of React. 5. What are the reasons why browsers don't support JSX? Only JavaScript objects are supported by browsers, but JSX is not one of them. For this reason, JSX files must first be converted into JavaScript objects like Babel before being sent to the browser.

My Top 5 Best Practices for ReactJs

This blog post contains some tips I learned while migrating some JavaScript files to TypeScript of an open-source project. A Brief Introduction To TypeScript For those who may have never heard of TypeScript, It is a programming language originally developed and maintained by Microsoft that first appeared in October 2012. In terms of functionalities, TypeScript is just JavaScript plus some other features which include assigning static types to variables. Some Notes on TypeScript Because TypeScript is just a superset of JavaScript, every JavaScript code is a valid TypeScript code TypeScript files usually have the extension .ts TypeScript code is compiled to plain JavaScript code which is what browsers understand (Browsers don’t understand TypeScript). The good news is, if you know JavaScript, you already know a lot about TypeScript. Type System in TypeScript The use of a type system in any programming language is to check the validity of the supplied values before they are stored or manipulated by the program. This prevents the program from having any unexpected behaviors and ensures that the code behaves as expected. In TypeScript, you can assign types to the declared variables in the following way : let firstName: string = "ismail"; You can see more details about TypeScript and types in TypeScript on their very good official documentation Convert a JavaScript File to TypeScript Before you start migrating, you must make sure to have certain configurations set up very early in your project. This includes setting up the file and integrating TypeScript with all the tools you intend to use. You can check for further information. tsconfig.json this page TypeScript Configuration File Here is a good explanation of the role of the TypeScript configuration file from the official documentation: The presence of a tsconfig.json file in a directory indicates that the directory is the root of a TypeScript project. The tsconfig.json file specifies the root files and the compiler options required to compile the project. You can generate that file in your project with this simple command tsc --init You don’t have to use all the options present in the file generated. You can use only the options you need. Here is a simple boilerplate configuration file that you can use to start off your project {
  "include": ["./src/**"], 
  "compilerOptions": {
    "target": "es2020", 
    "module": "es2020", 
    "moduleResolution": "node",
    "allowJs": true,
    "strict": true,
    "noEmit": true
  }
} In this configuration file, you mainly tell the TypeScript compiler to take into account all the files in the src folder and to compile them in the ES2020 syntax. Start Migrating Your JavaScript Files to TypeScript Firstly, you don’t necessarily have to migrate all your JavaScript files. You can keep some in JavaScript format if you want. The first step in migrating to TypeScript is to rename your JavaScript files from to . If you are using JSX, you have to rename your file to . If you open your newly created file in some code editor supporting TypeScript, you might see some errors showing up. Your objective will be to get rid of those errors while still staying as close as possible to the TypeScript features. .js .ts .tsx Cannot find a module The first error you might encounter is some modules that might not be found in your import statements. This just means that the modules aren’t defined in the declaration file in your project. What you have to do is install those missing modules prefixed by . A package name prefixed by is, simply put, just a customized version of that package for TypeScript. As an example, if TypeScript does complain that React is missing, you can fix that easily by installing @types/react in the following way @types @types npm install --save-dev @types/react Dealing with Types As we previously mentioned, one big advantage of using TypeScript is assigning types to variables. Doing so increases the readability of the program and makes it less prone to having bugs. Below are some remarks to keep in mind when you will be assigning types to variables. The type is the supertype of all types in TypeScript. It refers to a dynamic type. Using the type is equivalent to removing type checking for a variable. This should be used only as a last resort because you won’t be benefiting from type checking when using it. Dealing with the “ ” type : any any any When some variable in your code can be null or undefined, you can explicitly tell TypeScript that it isn’t with the exclamation mark. Dealing with null or undefined : function computeGlobalGrade(studentName: string | undefined | null) {
    const nameOne: string = studentName;
    // Typescript will complain that the student name might be null and cannot be assigned to a string

    const nameTwo: string = studentName!;
    // compiles fine because you tell compiler that null | undefined are excluded 
} If you have a list of properties like in a JavaScript Object, you can type them using either the keyword or by creating an . Both are correct usages, but using interfaces provides the additional benefit usually used in Object-Oriented programming languages that they can be extended. Typing a list of properties : type interface As an example, if you are converting a React component from JSX to TSX, and there is a PropTypes list defined like in the following : const propTypes = {
  i18nCertText: PropTypes.string,
  isProjectsCompleted: PropTypes.bool,
  steps: PropTypes.string,
  superBlock: PropTypes.string
}; You can convert that using either an in your TypeScript file as shown below interface interface ClaimCertStepsProps {
  i18nCertText: string;
  isProjectsCompleted: boolean;
  steps: string;
  superBlock: string;
} or using the keyword as shown below type type ClaimCertStepsProps = {
  i18nCertText: string;
  isProjectsCompleted: boolean;
  steps: string;
  superBlock: string;
} and then use that in your component in the following way const ClaimCertSteps = ({
  isProjectsCompleted,
  i18nCertText,
  steps,
  superBlock
}: ClaimCertStepsProps): JSX.Element => {
  // code of the component

} Adding a List of Properties To an Object One typical block of code we find in JavaScript programs is dynamically adding properties to an object like so let students = {};
students.name = "ismail";
students.age = 15; If you use the same code in TypeScript, the compiler will complain that the name and age properties does not exist on the students variable which has the type {}. To get rid of that error, you can define the properties inside the object like so : let student = {
  name: "ismail",
  age: 15,
} Or you can define the types of the properties in a separate interface like so : interface SudentProperties {
    name?: string,
    age?: number
}

let student: SudentProperties = {};

student.name = "ismail";
student.age = 15; Final words Migrating a project to TypeScript is not that much of a hassle. As every JavaScript code is a valid TypeScript code, you can choose to only convert the files where you need strict typing and then go over the remaining files as you want. The list above of tips is far from being exhaustive. There is a on the official TypeScript documentation that provides more information. guide If this post was helpful to you in any way, please don't hesitate to share it. You can also follow or visit if you would like to see more content related to web programming. my Twitter account my website

Quick Tips For Migrating from JavaScript to TypeScript

When you are writing a react application, you have two ways to handle  errors: Using try-catch block in each component Using React Error Boundary (only available in class Component :( ) import * as React from 'react'
import ReactDOM from 'react-dom'

function City({name}) {
  return <div>Hello, visit {name.toUpperCase()}</div>
}

function Country({capital}) {
  return <div>Hello, visit {capital.toUpperCase()}</div>
}

function App() {
  return (
    <div>
      <Country />
      <City />
    </div>
  )
}

ReactDOM.render(<App />, document.getElementById('root')) The above piece of code would end up showing you an error page when you run it in Development or a blank screen in Production. Obviously, the error we created in the code above could have certainly been handled with PropTypes or TypeScript. However, we are aware runtime error happens all the time, and we are going to deal with them using the two approaches stated above. Try/catch import * as React from 'react'
import ReactDOM from 'react-dom'

function ErrorHandler({error}) {
  return (
    <div role="alert">
      <p>An error occurred:</p>
      <pre>{error.message}</pre>
    </div>
  )
}

function City({name}) {
  try {
    return <div>Hello, visit {name.toUpperCase()}</div>
  } catch (error) {
    return <ErrorHandler error={error} />
  }
}

function Country({capital}) {
  try {
    return <div>Hello, visit {capital.toUpperCase()}</div>
  } catch (error) {
    return <ErrorHandler error={error} />
  }
}

function App() {
  return (
    <div>
      <Country />
      <City />
    </div>
  )
}

ReactDOM.render(<App />, document.getElementById('root')) This approach requires us to define an ErrorHandler component to display in case an error occurs, and we wrap each component returned element in the try/catch block. This seems ok, but repetitive. What if we want the parent component to handle the error catching for us. Wrapping the parent component in a try/catch block will not work, due to the nature of how React calls functions. That is when React Error Boundary comes in. According to React , React Error Boundaries are defined as follow: website Error boundaries are React components that catch JavaScript errors anywhere in their child component tree, log those errors, and display a fallback UI instead of the component tree that crashed. Error boundaries catch errors during rendering, in lifecycle methods, and in constructors of the whole tree below them. As at React 17.0.2, Error Boundary works only in Class component and It must implement or static getDerivedStateFromError() componentDidCatch() In order to use Error Boundary in Functional Component, I use . react-error-boundary import * as React from 'react'
import ReactDOM from 'react-dom'
import {ErrorBoundary} from 'react-error-boundary'


function ErrorHandler({error}) {
  return (
    <div role="alert">
      <p>An error occurred:</p>
      <pre>{error.message}</pre>
    </div>
  )
}

function City({name}) {
    return <div>Hello, visit {name.toUpperCase()}</div>
}

function Country({capital}) {
    return <div>Hello, visit {capital.toUpperCase()}</div>
}

function App() {
  return (
    <ErrorBoundary FallbackComponent={ErrorHandler}>
      <Country />
      <City />
    </ErrorBoundary>
  )
}

ReactDOM.render(<App />, document.getElementById('root')) When we run this application, we will get a nice error display from the content of catches any error from the components below them in the tree. This is really handy and useful because we need not declare a separate try/catch for each component because the wrapping component(ErrorBoundary) takes care of that and display the component of the provided. component. React error boundary FallbackComponent Exceptions to error handling Because uses in the background, there are a few exceptions to the errors that can be handled. react-error-boundary react error boundary These errors are not handled by react-error-boundary Event handlers Asynchronous code (e.g. setTimeout or requestAnimationFrame callbacks) Server-side rendering Errors thrown in the error boundary itself (rather than its children) Error recovery This library offers an error recovery feature that allows you to reset the state and bring back the components to a working point. Let's use this example from the react-error-boundary npmjs . page function ErrorFallback({error, resetErrorBoundary}) {
  return (
    <div role="alert">
      <p>Something went wrong:</p>
      <pre>{error.message}</pre>
      <button onClick={resetErrorBoundary}>Try again</button>
    </div>
  )
}

function Bomb() {
  throw new Error('💥 CABOOM 💥')
}

function App() {
  const [explode, setExplode] = React.useState(false)
  return (
    <div>
      <button onClick={() => setExplode(e => !e)}>toggle explode</button>
      <ErrorBoundary
        FallbackComponent={ErrorFallback}
        onReset={() => setExplode(false)}
        resetKeys={[explode]}
      >
        {explode ? <Bomb /> : null}
      </ErrorBoundary>
    </div>
  )
} The component accepts two other props to help recover from a state of error. The first prop receives a function that will be triggered when of the is called. The function is used to reset the state and perform any cleanup that will bring the component to a working state.
The other prop of is , it accepts an array of elements that will be checked when an error has been caught. In case any of these elements changes, the will reset the state and re-render the component. ErrorBoundary onReset resetErrorBoundary FallbackComponent onReset ErrorBoundary resetKeys ErrorBoundary Handling errors in React functional components should be a breeze for anyone using the library. It provides the following features: react-error-boundary Fallback components to display in case of error Granular capturing of error at the component level Recovery of error using a function or by resetting the elements causing the component to fail.

Error Handling in React Applications 

We’re introducing - 's enterprise feature. Merge UXPin Let's look at how easy it is to integrate a React-based library into Merge to design with code on a day-to-day basis. All that without designers learning how to code! UXPin Merge lets designers import developer’s existing custom React components in a seamless fashion to create interactive prototypes using real code, which is unlike anything else traditional design tools offer. This eliminates the need for designers to manually maintain a “second” design system within their design tool and instead provides the entire team with a single source of truth. The result? The disconnect between designers and developers is gone when building digital products. We want to save you time so we’ve designed this tutorial to integrate with Merge. After the integration, you’ll be able to use the app’s components to design an interactive Todo list prototype within UXPin! Mozilla’s React Todo App example Remember to start by requesting access to Merge – you can After the verification process and the setup, you’ll be ready to design with code! Also, don’t worry about integrating with GitHub – we don’t have any requirement of where the codebase should be located, so you can use whatever you want! do it here. The components The Todo app has three React components: – create a todo item. Form – filter todos by their current state. FilterButton – a todo list item. Todo These components are in the `src/components` directory and are outlined in the screenshot below: When this tutorial is completed, a designer will be able to create a prototype with these components. Your real-world custom design system (DS) likely has many more than three components. However, the concepts we’ll illustrate in this tutorial should apply to your DS as well. Setup UXPin Merge To begin, fork then clones the following link . Then install our UXPin Merge NodeJS package, which includes our CLI. https://github.com/mdn/todo-react into your project folder cd todo-react Navigate UXPin Merge and It’s CLI NodeJS bundle with: yarn add @uxpin/merge-cli–dev Install the UXPin Merge build directory with: echo ‘/.uxpin-merge’ >> .gitignore Ignore A custom design system requires two additional config files: uxpin.webpack.config.js uxpin.config.js UXPin typically doesn’t need to use your entire existing Webpack build process. We’ll use a more minimal and default build for UXPin. Create a uxpin.webpack.config.js file and paste the following code into it: path = ( ); webpack = ( ); .exports = { : { : path.resolve(__dirname, ), : , : }, : { : [__dirname, ], : [ , , ]
    }, : , : { : [
        { : , : [
            { : },
            { : , : { : }
            },
          ]
        },
        { : , : , : , : { : [ , ],
          }
        },
      ]
    }
} const require "path" const require "webpack" module output path "build" filename "bundle.js" publicPath "/" resolve modules "node_modules" extensions "*" ".js" ".jsx" devtool "source-map" module rules test /\.(s*)css$/ use loader 'style-loader' loader 'css-loader' options importLoaders 2 loader "babel-loader" test /\.js?$/ exclude /node_modules/ options presets '@babel/preset-env' '@babel/preset-react' For components you want to use in UXPin merge, you must specify their file directory in the uxpin.config.js file at the top of the directory of the repo. As you can see in the code snippet below, we’ve only added the ‘Form’ component src/components/Form.js  for now and will add the other components later in the tutorial. Create a uxpin.config.js and paste the following content into the file: .exports = { : { : [
      { : , : [ ,
        ]
      }
    ], : ,
  }, : }; module components categories name 'General' include 'src/components/Form.js' webpackConfig 'uxpin.webpack.config.js' name 'Learn UXPin Merge - React Todo list tutorial' Lastly, Babel-loader will be used by Webpack to create the app bundle. To install babel use the following commands: yarn add babel-loader –dev then yarn install . CONGRATULATIONS👏 You’re all good to go and have the minimum configuration required to view the Form component. Experimental Mode Experimental Mode lets us prototype with our local components to verify their behavior before pushing to UXPin. Now, to open UXPin Merge Experimental mode to preview the Form component, run ./node_modules/@uxpin/merge-cli/bin/uxpin-merge –disable-tunneling. In Experimental Mode, using –disable–tunneling makes requests go directly to your localhost web server. Quick note: UXPin with –disable-tunneling option works only in Chrome . Using the settings provided in `uxpin.webpack.config.js`, Experimental mode bundles your components and opens a browser window. You can lay out components in a similar fashion as the UXPin Editor. After Experimental Mode loads, drag and drop the Form component from the sidebar onto the project canvas: Using a Global Wrapper Component to apply CSS styles Just like your custom design system, this Todo app contains global styles. These are specified in the `src/index.css` file. All of our components need the styles specified in this file. We can load this file via a Global Wrapper Component. This component will wrap around every component we drag onto the UXPin canvas. Create a wrapper file: mkdir src/wrapper/ touch src/wrapper/uxpinwrapper.js Copy and paste the following into `UXPinWrapper.js`: React ; ; { children;
} import from "react" import '../index.css' export default ( ) function UXPinWrapper { children } return The `import ‘../index.css’;` line ensures our CSS styles are loaded prior to rendering each component. We need to tell UXPin to use this wrapper file. Add the following to uxpin.config.js: wrapper: , 'src/wrapper/UXPinWrapper.js' In your terminal, restart UXPin Experimental mode using ./node_modules/@uxpin/merge-cli/bin/uxpin-merge –disable-tunneling. A restart is required when updating the config file. A browser reload is only required when updating components. Experimental mode should open a new browser window with a styled Form component: Adding the FilterButton with a customizable name Now we’ll work on adding the FilterButton to UXPin Merge. These buttons are displayed below the Form component: Adding this component will be similar to the Form component. However, I’d also like to give designers the ability to specify the text that is displayed within the button. We’ll do that via the `prop-types` package. Component propTypes are mapped to the UXPin properties panel when editing a component. The existing FilterButton component doesn’t use prop-types so let’s add this to `FilterButton.js`: React ;
+ PropTypes ; { (
@@ , + , @@ {
  );
}
 
+ FilterButton.propTypes = {
+   name: PropTypes.string
+ }
 
+FilterButton.defaultProps = {
+  name: +}; FilterButton; import from "react" import from 'prop-types' ( ) function FilterButton props return -15 4 16 9 ( ) function FilterButton props 'Button Name' export default Add `’src/components/FilterButton.js’` to `uxpin.config.js` and restart using ./node_modules/@uxpin/merge-cli/bin/uxpin-merge –disable-tunneling. A restart is required as we’ve updated the config file. When Experimental Mode starts, you should see a new “FilterButton” component listed in the sidebar. Click and drag this onto the canvas. Two of our three components are now working with UXPin Merge. We have one component remaining: the Todo component. Adding the Todo component with a wrapper We’re moving on to our final component: the Todo. These are displayed within the list of todo items in the UI: When adding the FilterButton, we edited the FilterButton.js file to add propTypes. What if you want to isolate your Merge-specific changes and don’t want to modify the source code of your components? We can create a wrapper that is specific to the Todo component for this. It’s similar in concept to the Global wrapper component we used to apply CSS styles but will be specific to the Todo component. Type the following: mkdir -p src/components/merge/todo touch src/components/merge/todo/Todo.js Copy and paste the following code into Todo.js. React ; PropTypes ; TodoM ; { import from 'react' import from 'prop-types' // Import the original component import from '../../Todo' ( ) function Todo props return }
 
Todo.propTypes = {
  /**
   * If `true`, the todo will be marked as completed.
   */
  completed: PropTypes.bool,
 
  /**
   * The name of the todo.
   */
   name: PropTypes.string,
 
  toggleTaskCompleted: PropTypes.func,
}
 
Todo.defaultProps = {
  name: 'Do Laundry'
};
 
export default Todo; < { }/> TodoM ...props We’re importing the original Todo component as `TodoM` and returning this component in our newly defined `Todo` function. We specify propTypes just like we did with the FilterButton component on our newly defined `Todo` wrapper function. Add ‘src/components/merge/todo/Todo.js’ to uxpin.config.js and restart using ./node_modules/@uxpin/merge-cli/bin/uxpin-merge –disable-tunneling. After Experimental launches a new window, click-and-drag the Todo component onto the canvas: You’ll see the Todo component along with the default “Do Laundry” todo name. This default name is only applied when using Merge. Pushing to UXPin Until you push your design system to UXPin the components are only visible to you. To let your design team use these components we need to push the component bundle to UXPin. Creating and pushing a Merge design library requires two steps: 1. Create the library within the UXPin UI a. Go to your UXPin account b. Enter the UXPin Editor c. Create a new library d. Select the option import React components e. Copy the Auth token (don’t share it with anyone and do not place it in any files checked into git repository. This token provides direct access to the library on your account.) The process looks like this: 2. Push the library via the uxpin-merge CLI Using the token created from the previous stop, run the following from within the project repo: ./node_modules/@uxpin/merge-cli/bin/uxpin-merge push –token YOUR TOKEN Your design team can now access the Merge library. Using the Merge library within UXPin Now that the Merge design library has been pushed its time to test it out within the UXPin editor: Reload the UXPin Editor in your browser. Select the “Learn UXPin Merge” design system in the bottom left corner of the editor. Click and drag the components from the sidebar to the canvas. You should have a solid looking prototype: How does a designer hand off a prototype back to a developer? Previewing and exporting Now that we’ve built a quick prototype in UXPin we’re ready to export it back to our app. We can preview the output and then use to copy and paste the JSX code for our components. Spec mode Click the play button in the upper right corner of the editor. Once the preview loads click the “Spec” link at the top. You can now click on the components and view the JSX code to generate them in the right panel: It’s great to push an initial version of our design system. However, you’ll likely need to push out quite a few updates over time. Pushing an update The FilterButton has a “pressed” state to indicate the currently active filter. Looking at the live React app, here’s the difference between the pressed and not-pressed state: Let’s add support for this state. Make the following change to `src/components/FilterButton.js`: FilterButton.propTypes = {
-   name: PropTypes.string
+   name: PropTypes.string,
+   isPressed: PropTypes.bool
} Commit the change to git and push to UXPin: git add. git commit -m “Added isPressed prop to button” ./node_modules/@uxpin/merge-cli/bin/uxpin-merge push –token YOUR TOKEN Merge components are automatically synced to the most recently pushed code. To show the latest, reload the tab showing the UXPin editor. Select a FilterButton. In the right panel of the editor you should see a new “isPressed” property. Select it to activate this state: Follow this same flow (git commit + uxpin-push) when you make future changes. Prototypes will automatically use the latest pushed version of components. Summary You’ve taken a React app and pushed its components to UXPin Merge. You’ve also learned how to push updates when you modify components or add new ones. Now your design team can use these components to create high-fidelity prototypes within the UXPin editor. You can browse the source code for this project on . To learn more advanced Merge techniques see our or reach out to us at . GitHub Merge docs hello@uxpin.com Don’t have UXPin Merge yet? First, remember to go through the process of requesting access to make the most of designing with code! Previously published at https://www.uxpin.com/studio/blog/design-with-code-tutorial/

Delete the Disconnect Between Designers and Developers with Merge

Overview Handling form is an extremely common usecase for web applications. In this post, let's explore a way to handle form inputs and validations using React without using a third-party library. Requirements We will cover the most popular functionalities that will apply for most usecases: callback for components using the form. onSubmit Validation for single input (front-end only). Validation , not . onSubmit onBlur Reset form. How does it work? We will create a Form context that will hold all the states and define all state interactions for all form inputs. When an input is mounted, certain information passed in these inputs will be used to supply to the Form context. When an input within the form context changes, it will submit its new value to form context. Form context receives the values and changes its state to new value and pass it down to the input (controlled input). When the form is submitted, it will run through all the validations that was registered when the input mounted and set the errors for specific fields. Those will then be passed down to the right input and rendered accordingly. The figure below summarizes the responsibilities for each type of component. Implementation Form State This form state needs to be able to hold 3 pieces of information: Form data - for user's input data. Validations - for field specific validations. Errors - for field specific errors. I think this object should be suffice to work with. FORM_STATE = { : {}, : {}, : {},
}; const data validators errors We will also make a convention that every input must have a unique name prop to identify itself. It is similar to how a regular HTML5 form has name property. <input> It is important for the name to be unique because we will use them as keys in our state structure. For example, an input with name will be store in as follow: first_name FORM_STATE { : { : ,
  }, : { : [fn()],
  }, : { : [ ],
  }
} data first_name "John" validators first_name errors first_name "error message" Form Context To inject form state and methods to every components that want to subscribe to it, we will use context provider pattern. You can read more about context . here In my understanding, context is a wrapper that inject props into any child component that subscribe to it through a consumer. There is a convenient way to subscribe to context by using hook. useContext We will also create an HOC to encapsulate the context subscription logic in one place so that our input can be as purely UI as possible. In other words, inputs are presentational components that will only listen to prop changes. Form context is the container that will hold most of the logic. Form Methods Let's go through step by step how form context should behave. Registration When an input is mounted, it should register itself with form context. On registration, we simply will copy validators from that input to store inside form context. When an input is unmounted, we should clear its validations, errors, and any data associated with that input. Here's the registration function. registerInput = {
    setFormState( { {
        ...state, : {
          ...state.validators,
          [name]: validators || []
        }, errors: {
          ...state.errors,
          [name]: []
        }
      };
    }); {
      setFormState( { { data, errors, : currentValidators } = { ...state }; data[name]; errors[name]; currentValidators[name]; {
          data,
          errors, : currentValidators
        };
      });
    };
  }; const ( ) => { name, validators } => state return validators // clear any errors // returning unregister method return => () => state // copy state to avoid mutating it const validators // clear field data, validations and errors delete delete delete return validators The registration function will return a function to unregister this input. It will only remove that input with the same name. Input data control Controlled inputs require us to use an onChange function to set a value somewhere, either in a redux store or in a state. In our form, we will hijack it and set a value in our form context before passing up the value. That way, the input itself is more flexible, although, it does come with some confusions. When an input changes, we simply set its value to our form context's object. Here is the implementation. data setFieldValue = {
    setFormState( { {
        ...state, : {
          ...state.data,
          [name]: value
        }, : {
          ...state.errors,
          [name]: []
        }
      };
    });
  }; const ( ) => name, value => state return data errors In addition to setting the input's data, we also clear its own errors under the assumption that if there was an error when the form submitted, user must have seen the inline errors. Now they're correcting the value for that field. Submission and validation Next, we have validation and submission part of the form. The process is simple. When user click submit, we'll run through every validators in form context, call the validator with 2 arguments: The value of the input. The data object as a whole. Why do we pass data object into validators? Technically, we don't have to, but I think it's nice to have the validator aware of the whole form data. That way, we can perform cross input validation if we want. If all validators return empty messages. It's good. The form will call callback. onSubmit If ANY validator return an error message, we'll set the errors hash with that input's name and error messages. The form is now invalid and callback will not be called. onSubmit Let's take a look at the implementation. validate = { { validators } = formState; setFormState( ({
      ...state, : {}
    })); (isEmpty(validators)) { ;
    } formErrors = .entries(validators).reduce( { { data } = formState; messages = validators.reduce( { value = data[name]; err = validator(value, data); [...result, ...err];
        }, []); (messages.length > ) {
          errors[name] = messages;
        } errors;
      },
      {}
    ); (isEmpty(formErrors)) { ;
    }
    setFormState( ({
      ...state, : formErrors
    })); ;
  }; const => () const // always reset form errors // in case there was form errors from backend => state errors if return true const Object ( ) => errors, [name, validators] const const ( ) => result, validator const const return if 0 return if return true => state errors return false It's important to note that we're running through all validators and collect all errors before returning. Otherwise, when user have errors in 2 fields, they'll have to fix one, submit, get another error, and fix the second field. That's it! We've got our form context ready. Here's the full code below. React, { useState } ; PropTypes ; { isEmpty } ; propTypes = { : PropTypes.object, : PropTypes.func.isRequired, : PropTypes.func
}; initState = { { : {
      ...props.initialValues
    }, : {}, : {}
  };
}; FormContext; { Provider } = (FormContext = React.createContext()); Form = { [formState, setFormState] = useState(initState(props)); onSubmit = {
    e.preventDefault(); (validate()) {
      props.onSubmit(formState.data);
    }
  }; validate = { { validators } = formState; setFormState( ({
      ...state, : {}
    })); (isEmpty(validators)) { ;
    } formErrors = .entries(validators).reduce( { { data } = formState; messages = validators.reduce( { value = data[name]; err = validator(value, data); [...result, ...err];
        }, []); (messages.length > ) {
          errors[name] = messages;
        } errors;
      },
      {}
    ); (isEmpty(formErrors)) { ;
    }

    setFormState( ({
      ...state, : formErrors
    })); ;
  }; onReset = {
    e.preventDefault();
    setFormState(initState(props)); (props.onReset) {
      props.onReset();
    }
  }; setFieldValue = {
    setFormState( { {
        ...state, : {
          ...state.data,
          [name]: value
        }, : {
          ...state.errors,
          [name]: []
        }
      };
    });
  }; registerInput = {
    setFormState( { {
        ...state, : {
          ...state.validators,
          [name]: validators || []
        }, errors: {
          ...state.errors,
          [name]: []
        }
      };
    }); {
      setFormState( { { data, errors, : currentValidators } = { ...state }; data[name]; errors[name]; currentValidators[name]; {
          data,
          errors, : currentValidators
        };
      });
    };
  }; providerValue = { : formState.errors, : formState.data,
    setFieldValue,
    registerInput
  }; ( <form
        onSubmit={onSubmit}
        onReset={onReset}
        className={props.className}
        id={props.id}
      >
        {props.children}
      </form> );
};

Form.propTypes = propTypes; Form; { FormContext }; import from "react" import from "prop-types" import from "lodash" const initialValues onSubmit onReset const => props return data validators errors let const const => props const const => e if const => () const // always reset form errors // in case there was form errors from backend => state errors if return true const Object ( ) => errors, [name, validators] const const ( ) => result, validator const const return if 0 return if return true => state errors return false const => e if const ( ) => name, value => state return data errors const ( ) => { name, validators } => state return validators // clear any errors // returning unregister method return => () => state // copy state to avoid mutating it const validators // clear field data, validations and errors delete delete delete return validators const errors data return < = > Provider value {providerValue} </ > Provider export default export Form HOC Now that we have form context, we will make an wrapper to inject those context methods into any input component. This is optional because you can always use a context hook. Though, I think it's convenient. The HOC will handle input registration, filtering errors and input value, and set data in form context. First, let's subscribe to form context with hook. useContext { 
  errors, 
  data, 
  setFieldValue, 
  registerInput 
} = useContext(
  FormContext
); const After that, we'll register to Form context with . useEffect useEffect( registerInput({ : props.name, : props.validators
    }),
  []
); => () name validators We also return the unregistration function, so when this input is unmounted, it will not affect the form data or its validations anymore. Then, we need to get the right input value and error for the wrapped input. inputValue = data[props.name]; inputErrors = errors[props.name] || []; const const Error will always be an array of error messages. Empty error array means there are no errors. Lastly, we need to hijack the onChange callback so we can store this wrapped input's value to form context. onChange = {
  setFieldValue(props.name, val); (props.onChange) {
    props.onChange(val);
  }
}; const => val if Here is the entire implementation. React, { useContext, useEffect } ; PropTypes ; { FormContext } ; propTypes = { : PropTypes.string.isRequired, : PropTypes.arrayOf(PropTypes.func)
}; withForm = { WrappedWithForm = { { errors, data, setFieldValue, registerInput } = useContext(
      FormContext
    );

    useEffect( registerInput({ : props.name, : props.validators
        }),
      []
    ); onChange = {
      setFieldValue(props.name, val); (props.onChange) {
        props.onChange(val);
      }
    }; inputValue = data[props.name]; inputErrors = errors[props.name] || []; ( import from "react" import from "prop-types" import from "./index" const name validators const => InputComponent const => props const => () name validators const => val if const const return );
  };

  WrappedWithForm.propTypes = propTypes;
  return WrappedWithForm;
};

export default withForm; < { } = = = /> InputComponent ...props errors {inputErrors} value {inputValue} onChange {onChange} Text Input Finally, something usable. Let's make a text input using our form. Our input will have the following: - A label - The input itself - Any errors - onChange callback It will receive in errors and value from form context. Based on form context, it will render accordingly. This is quite simple to implement. Here's the implementation. React ; PropTypes ; { isEmpty } ; classNames ; withForm ; ; propTypes = { : PropTypes.string, : PropTypes.string, : PropTypes.string, : PropTypes.string, : PropTypes.string, : PropTypes.arrayOf(PropTypes.string)
}; defaultProps = { : , : }; TextInput = { hasError = !isEmpty(props.errors); renderErrors = { (!hasError) { ;
    } errors = props.errors.map( ( )); ;
  }; onChange = { val = e.target.value;
    props.onChange(val);
  }; klass = classNames( , { : hasError
  }); ( <label>{props.label}</label> <input
        name={props.name}
        type={props.type}
        className="form-control"
        placeholder={props.placeholder}
        onChange={onChange}
        value={props.value}
      />
      {renderErrors()}
    </div> import from "react" import from "prop-types" import from "lodash" import from "classnames" import from "./with_form" import "./styles.css" const placeholder name value label type errors const value "" type "text" const => props const const => () if return null const ( ) => errMsg, i {errMsg} < = `${ } ${ }`} = > li key { props.name -error- i className "error" </ > li return {errors} < = > ul className "error-messages" </ > ul const => e const const "form-group" "has-error" return < = > div className {klass} );
};

TextInput.propTypes = propTypes;
TextInput.defaultProps = defaultProps;

const FormTextInput = withForm(TextInput);

export { TextInput };
export default FormTextInput; All together now! We've arrive to the end! Yay! Let's put together a sign up form as an example. <Form onSubmit={data => .log(data)}> <TextInput
    name="last_name"
    validators={[requiredValidator]}
    placeholder="Smith"
    label="Last Name"
  />
  // .... truncate
  <button className="submit-btn" type="submit">
    Register!
  </button>
  <button className="submit-btn danger" type="reset">
    Reset
  </button>
</Form> console < = = = = /> TextInput name "first_name" validators {[requiredValidator]} placeholder "John" label "First Name" We'll simply log out the data for now. We'll also put in a few validators to make sure that it works. Let's take a look at a sample validator. requiredValidator = { (!val) { [ ];
  } [];
}; const => val if return "This field is required" return Try clicking submit and reset to see how it works! (CodeSandbox below) Thank you for reading to this point. I hope this is useful. Let me know your thoughts and comments :) Form in action

How To Handle Form and Validation with React?

React-Redux Flow: Detailed Guide

Four ways to make your React Native map become a lot faster and more responsive. Why this is important As a mobile developer working with React Native or any platform/language, you will sooner or later have to deal with maps. And when that time comes, you need to know how to optimize it effectively, because if not, your users’ experience will greatly suffer. In this article I will show you — in — how to make your map faster, smoother, and more responsive. 4 possible ways Putting a map and use it in your React Native application is dead simple because of . It’s a straightforward API, you only need to render a MapView to display a blank map, then render a bunch of Markers, which are essentially pins on a map. react-native-maps If you are not familiar with react-native-maps, make sure to check out their before continue. documentation What the problem is The problem is, as with a lot of other components, the performance of a React Native map will . Displaying 5 Markers for your favorite cafes around the city would be a walk in the park; but let say, if your app shows all McDonald’s in the country, there will be of Markers if you zoom out large enough! You will certainly experience lags up to a point where your app is effectively unusable. get worse the more data it has to handle hundreds or thousands Photo credit: EduBirdie Delays in React Native are commonly caused by , simply means that your app renders components more frequently than it should, wasting a lot of time. They are usually caused by changes in (Markers in this case). If we only allow re-renders when necessary — when the state of the Marker itself changes — the performance of the Map would be significantly better. excessive re-rendering part of the state unrelated to the component So we identified the problem and came up with a solution. But before we go further, let me first give you a small relief: your map might not be as slow as it appears. If you happen to be viewing your app in the iOS Simulator on macOS, and you are using Google as your map provider like this: <MapView  style={{ : }}  provider= > flex 1 'google' I might have good news for you. For some reasons, the , while the default Apple map does not (just remove and you will see). To better access its performance on iOS, make sure to have an iPhone which you can test the app on. Google-provided map in React Native runs very slowly on iOS Simulator provider='google' How to solve it 1. Turn off trackViewChanges in custom Markers when not needed The component comes with a default parameter set to true. This parameter enables custom Markers to track changes in the view and be redrawn. If your application does not require this feature, simply set to false will significantly increase speed. Marker trackViewChanges trackViewChanges {Marker} ; { ( import from 'react-native-maps' export default ( ) function MyMarker return );
} < = = = = = = /> Marker key {pin.id} coordinate {pin.coord} title {pin.name} onPress {onPinChosen} image {../assets/pin.png} tracksViewChanges {false} 2. React.memo, or shouldComponentUpdate, or PureComponent Another way to minimize rendering is to only allow your to be re-rendered when its . Marker props actually change (and usually they don’t: when is the last time your house move when you’re looking at it on the map?) React provide us with (for function components) and (for class components). Alternatively, you can also use to achieve the same result as React.memo shouldComponentUpdate React.PureComponent shouldComponentUpdate Firstly, an example of : React.memo React ; { Marker } ; { {coord} = props; ( import from 'react' import from 'react-native-maps' ( ) function CarPin props const return );
}
export default CarMarker = React.memo(CarPin); < = = /> Marker coordinate {coord} tracksViewChanges {false} an example of : shouldComponentUpdate React ; { Marker } ; {
  shouldComponentUpdate(nextProps) { nextProps.coord !== .props.coord
  }
  render(){ ( import from 'react' import from 'react-native-maps' export default . class CarPin extend React Component return this return );
  }
} < = = /> Marker coordinate {this.props.coord} tracksViewChanges {false} and an example of : React.PureComponent React ; { Marker } ; {
  render(){ ( import from 'react' import from 'react-native-maps' export default . class CarPin extend React PureComponent return );
  }
} < = = /> Marker coordinate {this.props.coord} tracksViewChanges {false} Make sure to check out , and official documentation if you want to further customize the behavior of your component. React.memo shouldComponentUpdate React.PureComponent 3. Use “icon” instead of “image” to build your custom Marker The performance difference is not explicitly said in the documentation, but according to the : official source code image: PropTypes.any, icon: PropTypes.any, /**
  * A custom image to be used as the marker's icon. Only local image resources are allowed to be used.
  */ /**
  * Marker icon to render (equivalent to `icon` property of GMSMarker Class).Using this property has an advantage over `image` in term of performance, battery usage... because it doesn't trigger tracksViewChanges. (tracksViewChanges is set to YES by default if iconView is not nil).
  */ 4. Cluster your Markers Instead of explaining what clustering means in this case, let me show you an example from . The images below shows a map clustering (left) and a map clustering (right) an app I built with without Map clustering can be done easily using APIs such as or react-native-map-clustering @bam.tech/react-native-component-map-clustering While the difference in is already impressive, the difference in is even more amazing. To understand why, we have to look at how map clustering works: appearance performance First, the API will count the number of Markers located in a (relatively) small region on the . Instead of rendering the Markers, it will render the number of Markers on the map. When the user zoom in or zoom out, the number will be calculated again. When the user zoom in enough, the actual Markers will be displayed. MapView This means, the app will save a lot of time from rendering a whole bunch of Markers. Instead it will only count and render the number of Markers. — since the app will have to count the number of Markers every time the user zooming in or out, make sure that the trade off between rendering time and recounting time is worth it. This is also where you should be careful Conclusion Optimizing React Native map, while relatively simple, is not something straightforward that is automatically done for you by the APIs. In this article I have listed 4 different ways to do that: Turn off in custom Markers when not needed. trackViewChanges Use , or , or . React.memo shouldComponentUpdate React.PureComponent Use “icon” instead of “image” to build a custom Marker. Cluster your Markers. I hope by using a these tips, you will be able to build faster, more responsive applications that can provide a superb user experience. Best of luck! If you are interested in what I do, or want to contact me, feel free to send me an email , visit my Github and connect with me on LinkedIn .

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