Use a JavaScript code linter to enforce coding standards and catch errors early

Here's an example of using ESLint, a popular JavaScript linter, in a Node.js project:

First, you'll need to install ESLint globally if you haven't already:

npm install -g eslint

Next, initialize ESLint in your project:

eslint --init

Follow the prompts to set up ESLint according to your preferences. Once configured, ESLint will create an .eslintrc.js or similar file in your project directory.

Here's an example of what an .eslintrc.js file might look like:

module.exports = {
  "env": {
    "browser": true,
    "node": true,
    "es6": true
  },
  "extends": "eslint:recommended",
  "parserOptions": {
    "ecmaVersion": 2018
  },
  "rules": {
    "indent": ["error", 2],
    "linebreak-style": ["error", "unix"],
    "quotes": ["error", "single"],
    "semi": ["error", "always"]
  }
};

This configuration enables ESLint to lint JavaScript files in a Node.js environment, using ECMAScript 2018 syntax. It also enforces rules such as 2-space indentation, Unix line endings, single quotes for strings, and semicolons at the end of statements.

To lint your JavaScript files, run ESLint from the command line in your project directory:

eslint yourfile.js

ESLint will analyze your JavaScript code, applying the rules specified in your .eslintrc.js file, and report any errors or warnings it finds.