Adding more tools to control code quality

Last month, I had to work with different Static Analysis tooling like Prettier, Flake8, esLint as required by those open source projects to make their code style identical and at good quality.

This week, I have a chance implement them into my project as an author to ensure my code stay consistent when different people contribute. The extensions I chose to add to the workflow are:

• Prettier
• ESLint
• Editor/IDE Integration(.vscode/)
• Git Pre-Commit Hook(husky and lint-staged)

Prettier

This code formatter is very popular in the Web-dev community as it:

• An opinionated code formatter
• Supports many languages
• Integrates with most editors
• Has few options
• Doesn't take long to configure

To install Prettier, firstly run

npm install --save-dev --save-exact prettier

Create 2 files .prettierrc.json and .prettierignore. Add formatting options to .prettierrc.json and choose what files/folders to ignore by editing .prettierignore.

However, if you are using Windows, it's better to manually create these 2 files rather than using echo{} like in the docs as the command will create UTF-16LE encoded files.

ESLint

ESLint is also a powerful to detect and fix linting problems in your JavaScript code. You can install ESLint running

npm isntall eslint --save-dev      
npx eslint --init  

Edit your .eslintrc.json to your reference, it supports different plugins and configuration files aside from its normal options, you can take a look at mine

{
  "env": {
    "node": true,
    "commonjs": true,
    "es2021": true
  },
  "extends": "eslint:recommended",
  "parserOptions": {
    "ecmaVersion": "latest"
  },
  "rules": {
    "semi": ["error", "always"],
    "quotes": ["error", "double"],
    "require-atomic-updates": "error",
    "max-len": ["warn", { "code": 200 }]
  }
}

Editor Integration

Integrating these static analysis tools into the editor makes it smoother as we can see what changes and what is wrong while writing code rather in build time.

My approach is too create a .vscode/ folder containing settings.json that configures the VSCode editor settings directly and recommendations.json that has VSCode recommended extensions.

Adding a pre-commit hook:

Why husky and lint-staged? husky a JS package for defining and executing git hooks and lint-staged is used to run linters against your staged files, in our case we're using it with the pre-commit hook

npm install --save-dev lint-staged husky
npx husky-init 

Add these your package.json file

"husky": {
    "hooks": {
      "pre-commit": "lint-staged"
    }
  },
  "lint-staged": {
    "*.js": [
      "npx prettier --write",
      "npx eslint"
    ]
  }

.husky/pre-commit file

#!/bin/sh
. "$(dirname "$0")/_/husky.sh"

npx eslint .

husky works according to the script hooks we specify in the object we within in the package.json file and lint-staged will perform the 2 line scripts on files with js extension. With these configurations, whenever you try to commit, the pre-commit hook will make sure to format the code and show you linting errors.