Linting
Contents
ESLint is a static code analysis tool for identifying problematic patterns found in JavaScript code.
ESlint is highly configurable and can be used to enforce a consistent coding style. Having linting as a part of the build process is considered a good practice.
Install
npm install --save-dev eslint @eslint/js typescript-eslintConfigure
package.json
Add the following scripts to the package.json file:
{
"scripts": {
"check": "concurrently -c auto -g --timings npm:check:types npm:lint",
"lint": "eslint --cache",
}
}Note that check command was added to package.json in the previous chapter about type checking. Here we just modify it to execute linting as a part of the check command. |
eslint.config.mjs
Create the following file:
eslint.config.mjs
import eslint from '@eslint/js';
import tseslint from 'typescript-eslint';
export default tseslint.config(
// If ignores is used without any other keys in the configuration object,
// then the patterns act as global ignores.
{
// An array of glob patterns indicating the files that the configuration
// object should not apply to. If not specified, the configuration
// object applies to all files matched by files.
ignores: [
'build/**/*.*',
'src/jest/server/setupFile.ts',
'tsup/*.*',
],
},
eslint.configs.recommended,
...tseslint.configs.recommended,
{
// An array of glob patterns indicating the files that the configuration
// object should apply to. If not specified, the configuration object
// applies to all files matched by any other configuration object.
files: [
'./src/**/*.ts',
'./src/**/*.tsx'
],
rules: {
'@typescript-eslint/no-unused-vars': [
"warn",
{
"argsIgnorePattern": "^_"
}
]
}
}
);Linting will now be executed as a part of the check command and, therefore, as a part of the build process.
