Automating open source project configuration with Mrm

We use many tools, like linters, test runners and continuous integration, to make our life as developers easier. But maintaining configuration for these tools is far from easy, especially if you want up-to-date configs in all your projects. tries to solve this problem. Mrm . Slightly different files. Photo by yours truly What’s the problem The only thing that many times was preventing me from extracting some generic function to a separate package is a need to copy and modify a dozen of config files — all that s — just to publish a 50-line function. .somethingrc These support files are usually only in all your projects. For example, a file has and editor artifacts that you want to share between all your projects, but some projects have extra lines there that you don’t want in other projects. We need a way to keep in sync the common parts but allow per-project customizations. slightly different .gitignore node_modules Template-based tools, like Yeoman, are good for initial project bootstrapping but don’t work well for updates: they would overwrite a file with a new version and you’ll lose your customizations. What’s Mrm takes a different approach. It works similar to : instead of a template that would overwrite everything, you’re describing in code how to or create files to achieve the desired state of the file. Mrm codemods modify Minimal changes Mrm tries to do minimal changes by inferring indentation style or reading it from the EditorConfig, and keeping comments in JSON files. Minimal config It has minimal required configuration: it’ll use values from the project itself or from the environment, like reading your name and email from your Git or npm configs. Focused but rich API Mrm has utilities to work with popular config file formats: JSON, YAML, INI and new line separated text files; install npm packages; and file operations. This allows you to create smart , so the result depends on your project needs. tasks Available tasks Mrm has out of the box: CodeCov, EditorConfig, ESLint, .gitignore, Jest, lint-staged, Prettier, semantic-release, React Styleguidist, stylelint, Travis CI, TypeScript, package.json, contributing guidelines, license and readme file. You can create your own task or combine multiple tasks using aliases. many tasks For example, the : Jest task adds npm scripts to run Jest; adds configuration to if needed; package.json updates , , with common patterns; .gitignore .npmignore .eslintignore installs Jest, , or Enzyme if needed; babel-jest ts-jest tries to get rid of Mocha and AVA configs and dependencies; suggests to us if projects used other test frameworks. jest-codemods Or the that will add new lines to the file but won’t remove per-project customizations: gitignore task .gitignore Installation and usage Install Mrm from npm: npm install -g mrm And run like this: mrm gitignoremrm license --config:licenseFile Or run Mrm via without installation: npx npx mrm gitignorenpx mrm license --config:licenseFile Optionally, create a config file at or instead of passing values via command line: ~/.mrm/config.json ~/dotfiles/mrm/config.json { "github": "sapegin", "eslintPreset": "airbnb", "aliases": { // Aliases to run multiple tasks at once "node": ["license", "readme", "editorconfig", "gitignore"] }} See more usage examples and options . in the docs Creating your own tasks The real power of Mrm is in custom tasks and that gives you tools to work with config files, dependencies, file operations, etc. mrm-core library The simplest task could look like this: // Mrm module to work with new line separated text filesconst { lines } = require('mrm-core');function task() { // Read .gitignore if it exists lines('.gitignore') // Add lines that do not exist in a file yet, // but keep all existing lines .add(['node_modules/', '.DS_Store']) // Update or create a file .save();}task.description = 'Adds .gitignore';module.exports = task; See more examples . in the docs You can save your tasks locally, or combine multiple tasks . publish them on npm in a preset Conclusion If you have many projects with a similar stack or a big multi-repository project, may be a good way to manage their configuration and could save your time. Mrm Start with default tasks and then write your own or create a preset for your project or organization. The project is still young — let me know what you think in comments or . GitHub issues P.S. Check out our new book on . JavaScript projects maintenance Thanks to Anna Gerus , Karl Horky , Andrey Okonetchnikov , Oleg Slobodskoi , Olga Sylenko, Juho Vepsäläinen .