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Hackernoon logoReactJS Pagination Tutorial: Building from Scratch by@codebucks

ReactJS Pagination Tutorial: Building from Scratch

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@codebucksCodeBucks

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Hey Everyone,

Hope you all doing great.

In this post we're building pagination component from scratch in ReactJS. We're not going to use any library here.

If you prefer to watch video then you can go through below video else keep reading...😄

Let's start by creating our react-app,

npx create-react-app react-pagination-component

Create a separate file, like PaginationComponent.js.

Here, I'm using jsonplaceholder API to get data and use pagination on that data.

This API will return us a list of todos. Now to store this data create one state and initialize it with an empty array.

const [data, setData] = useState([]);

Now let's use useEffect to set this state with our data which comes from API.

useEffect(() => {
    fetch("https://jsonplaceholder.typicode.com/todos")
      .then((response) => response.json())
      .then((json) => setData(json));
  }, []);

if you want to see what type of data this api is providing then just go to this url.

Also if you don't know how to fetch api in ReactJS you can watch my video on How to fetch API.

let's create a small renderData component outside of our main component to render the "to-do" list.

import React, { useEffect, useState } from "react";
import "./style.css";

const renderData = (data) => {
  return (
    <ul>
      {data.map((todo, index) => {
        return <li key={index}>{todo.title}</li>;
      })}
    </ul>
  );
};

function PaginationComponent() {
  const [data, setData] = useState([]);

  useEffect(() => {
    fetch("https://jsonplaceholder.typicode.com/todos")
      .then((response) => response.json())
      .then((json) => setData(json));
  }, []);

  return (
    <>
      <h1>Todo List</h1> <br />
      {renderData(data)}
   
    </>
  );
}

export default PaginationComponent;

In const renderData here I have mapped title of to-dos from data state.

and Render {renderData(data)} with data state, inside the return.

Now, let's create pagination from here.

To do that we need two states,

const [currentPage, setcurrentPage] = useState(1);
const [itemsPerPage, setitemsPerPage] = useState(5);

currentPage :- stores current page number, initially 0.

itemsPerPage :- stores no of items we want to display in single page. Initially it is 5.

  const pages = [];
  for (let i = 1; i <= Math.ceil(data.length / itemsPerPage); i++) {
    pages.push(i);
  }

In above code,

pages array contains total number of pages like 1,2,3..upto (total data / itemsPerPage).

If you have 20 items and you want to display 5 items per page then you will need 20/5 = 4 pages.

Let's create render page number component which will display page numbers.

import React, { useEffect, useState } from "react";
import "./style.css";

const renderData = (data) => {
  return (
    <ul>
      {data.map((todo, index) => {
        return <li key={index}>{todo.title}</li>;
      })}
    </ul>
  );
};

function PaginationComponent() {
  const [data, setData] = useState([]);

  useEffect(() => {
    fetch("https://jsonplaceholder.typicode.com/todos")
      .then((response) => response.json())
      .then((json) => setData(json));
  }, []);
  
  const handleClick = (event) => {
    setcurrentPage(Number(event.target.id));
  };
  
   const renderPageNumbers = pages.map((number) => { 
      return (
        <li
          key={number}
          id={number}
          onClick={handleClick}
          className={currentPage == number ? "active" : null}
        >
          {number}
        </li>
      );
    
  });
  

  return (
    <>
      <h1>Todo List</h1> <br />
      {renderData(data)}

      <ul className="pageNumbers">
       {renderPageNumbers}
      </ul>

    </>
  );
}

export default PaginationComponent;

As you can see after the handleClick method at renderPageNumber,

I have mapped this pages array which will return an

li  
tag which display page numbers. This
li
tag contains key, id, onClick method and className.

Here className becomes active when you are on the same page as currentPage state.

This handleClick method runs when we click on any page number and set currentPage state to selected page number.

Now inside the return render renderPageNumbers component by wrapping it with

ul
tag and className as pageNumbers.

NOTE: For styling, you can refer this css file.

As you have observed, This page numbers are all over whole page and now we need to set limit to display this page numbers.

To do that we need to define 3 more react states.

  const [pageNumberLimit, setpageNumberLimit] = useState(5);
  const [maxPageNumberLimit, setmaxPageNumberLimit] = useState(5);
  const [minPageNumberLimit, setminPageNumberLimit] = useState(0);

pageNumberLimit is to store how many page numbers you want to display. Here I want to display only 5.

maxPageNumberLimit is to store max page bound limit.

minPageNumberLimit is to store min page bound limit.

Now modify renderPageNumbers component by putting if condition like given below,

const renderPageNumbers = pages.map((number) => {
    if (number < maxPageNumberLimit + 1 && number > minPageNumberLimit) {
      return (
        <li
          key={number}
          id={number}
          onClick={handleClick}
          className={currentPage == number ? "active" : null}
        >
          {number}
        </li>
      );
    } else {
      return null;
    }
  });

This if condition means that if current number is greater then maxPageNumberLimit+1 and less then minPageNumberLimit then render it else render nothing.

As you run your code, you will see that there are only 5 page numbers displayed.

Next we need next and previous buttons.

Create those buttons around the

{renderPageNumbers}
component.

Just like below,

import React, { useEffect, useState } from "react";
import "./style.css";

const renderData = (data) => {
  return (
    <ul>
      {data.map((todo, index) => {
        return <li key={index}>{todo.title}</li>;
      })}
    </ul>
  );
};

function PaginationComponent() {
  const [data, setData] = useState([]);

  useEffect(() => {
    fetch("https://jsonplaceholder.typicode.com/todos")
      .then((response) => response.json())
      .then((json) => setData(json));
  }, []);
  
  const handleClick = (event) => {
    setcurrentPage(Number(event.target.id));
  };
  
   const renderPageNumbers = pages.map((number) => { 
      return (
        <li
          key={number}
          id={number}
          onClick={handleClick}
          className={currentPage == number ? "active" : null}
        >
          {number}
        </li>
      );
    
  });
  
    const handleNextbtn = () => {
    setcurrentPage(currentPage + 1);

    if (currentPage + 1 > maxPageNumberLimit) {
      setmaxPageNumberLimit(maxPageNumberLimit + pageNumberLimit);
      setminPageNumberLimit(minPageNumberLimit + pageNumberLimit);
    }
  };

  const handlePrevbtn = () => {
    setcurrentPage(currentPage - 1);

    if ((currentPage - 1) % pageNumberLimit == 0) {
      setmaxPageNumberLimit(maxPageNumberLimit - pageNumberLimit);
      setminPageNumberLimit(minPageNumberLimit - pageNumberLimit);
    }
  };
  

  return (
    <>
      <h1>Todo List</h1> <br />
      {renderData(data)}

      <ul className="pageNumbers">
        <li>
          <button
            onClick={handlePrevbtn}
            disabled={currentPage == pages[0] ? true : false}
          >
            Prev
          </button>
        </li>
        {renderPageNumbers}
        <li>
          <button
            onClick={handleNextbtn}
            disabled={currentPage == pages[pages.length - 1] ? true : false}
          >
            Next
          </button>
        </li>
      </ul>

    </>
  );
}

export default PaginationComponent;

There are two buttons prev and next, before and above the

{renderPageNumbers}
.

In handleNextbtn method for next button. In this method whenever user clicks on next button, it will set the current page state to plus 1. and check the condition if current page has not crossed maximum page number limit or not. If yes then it will reset this max and min page number limit with new limit.

In handlePrevbtn method for previous button. Only change is in the sign and in if condition. Suppose you are at page 6 and you want to go back to 5 then this condition will check that 6-1=5%5==0 so it will become true and it will reset max and min page number limits.

Below code is to disable next button,we will disable next button when user is at last page.

disabled={currentPage == pages[pages.length - 1] ? true:false}

Below code is to disable Prev button, we will disable prev button when user is at 1st page.

disabled={currentPage == pages[0] ? true : false}

Now our Pagination component is Almost completed one thing left is to add those three dots which indicates that there are more pages then displayed.

Let's create them.

Above is the full code for this Tutorial.

Just before the return I have created two buttons with hellip; which is unicode for ...

There are two buttons pageIncrementBtn will render when page length is > maxPageNumberLimit. while pageDecrementBtn will render when minPageNumberLimit >= 1.

Don't forget to render both of this ... buttons below and after the {renderPageNumbers} component.

Now your whole Pagination component is completed.

Watch above given video to know about one more pagination component which loads items vertically.

Thanks For Reading.😄

Also published here.

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