cli Archives | JS FAQ - JavaScript Guides Online

Lifecycle hooks are essential for managing Angular component behavior. Key hooks include ngOnInit for initialization, ngOnChanges for responding to data-bound changes, and ngOnDestroy for cleanup activities. Proper use of these hooks ensures efficient resource management and enhances application performance, maintaining a responsive and maintainable codebase.

Build Tools

How to create a Makefile for JavaScript project builds

Build Toolsautomation, build, cli, makefile

Makefiles streamline JavaScript workflows by defining targets, prerequisites, and recipes. Essential components include transpilation using Babel and minification with Terser. Variables enhance maintainability, while automated testing ensures code quality. Create a robust build process that adapts to project needs effortlessly.

Code Quality: ESLint/Prettier

How to fix linting errors automatically with ESLint

Code Quality: ESLint/Prettierautofix, cli, eslint, fix

ESLint installation and usage via npm or yarn, running lint checks with npx eslint, fixing issues using the --fix flag, targeting specific files or directories, and integrating ESLint into package.json scripts for automated linting in development workflows.

Code Quality: ESLint/Prettier

How to run ESLint from the command line

Code Quality: ESLint/Prettiercli, eslint, lint, terminal

ESLint error messages provide essential details, including file name, line number, severity, and rule violation. Understanding these messages helps in fixing issues effectively. Key practices involve using the --fix option, managing warnings, disabling rules when necessary, and keeping ESLint updated for optimal code quality and maintainability.

E2E Testing: Cypress

How to run Cypress tests from the command line

E2E Testing: Cypresscli, command, cypress

Execute Cypress tests via the command line with `npx cypress run`. Configure runs with flags like `--spec`, `--browser`, and `--config`. Speed up CI builds using parallel execution and stub network requests with `cy.intercept()`. Includes tips on programmatic login and managing test reporters for efficiency.

Transpilers: Babel

How to transpile JavaScript using Babel CLI

Transpilers: Babelbabel, cli, javascript, transpile

Fix JavaScript browser compatibility by transpiling ES6 with Babel. Configure `@babel/preset-env` to target browsers and use polyfills for APIs like fetch. Improve your build process with npm scripts, `rimraf` for cleaning directories, and `npm-run-all` for running parallel tasks.

Unit Testing: Jest

How to run tests with Jest from the command line

Unit Testing: Jestcli, command, jest, run

Jest flags: --watch for Git-tracked changes, --watchAll for all files, --runInBand for serial debugging, --clearCache for errors, --findRelatedTests for specific files. Configure moduleNameMapper for path aliases. Debug with node --inspect-brk. Use jest.useFakeTimers() for timer tests.

Testing Frameworks

How to run tests from the command line in JavaScript

Testing Frameworksautomation, cli, testing

Prevent broken merges with Git pre-commit hooks using husky and lint-staged for Jest tests and ESLint. Implement a server-side CI pipeline with GitHub Actions. Enforce passing tests before merging to the main branch with branch protection rules, making it impossible to merge broken code.

Node.js Core

How to access command-line arguments in Node.js

Node.js Coreargs, cli, node.js, process.argv

A Node.js command-line argument parser script for handling various formats: key-value pairs, boolean flags, single-dash flags (-v), combined flags (-xvf), and --key=value assignments. This JavaScript function processes process.argv and positional arguments, showing why yargs or commander are better.