@putout/eslint [![NPM version][NPMIMGURL]][NPMURL]

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[NPMURL]: https://npmjs.org/package/@putout/eslint "npm"

Wrapper that simplifies ESLint API and makes it compatible with 🐊Putout.

☝️ FlatConfig supported from the box.

Install

``
npm i @putout/eslint
`

Environment Variables

- ☝️ To set custom config file for ESLint use ESLINT_CONFIG_FILE env variable:
- ☝️ To disable ESLint support use NO_ESLINT=1 env variable:
- ☝️ If you want to ignore ESLint warnings (which is unfixable errors in 🐊Putout language) use NO_ESLINT_WARNINGS=1:

``sh
NO_ESLINT_WARNINGS=1 putout --fix lib

API

$3

ESLint begins his work as a formatter when 🐊Putout done his transformations. That's why it used a lot in different parts of application, for testing purpose and using API in a simplest possible way. You can access it with:

`js
import {eslint} from '@putout/eslint';
``

To use it simply write:

`js
const [source, places] = await eslint({
name: 'hello.js',
code: const t = 'hi'\n,
fix: false,
});
`

Isn't it looks similar to 🐊Putout way? It definitely is! But... It has a couple differences you should remember:

- ☝️ 🐊Putout returns object with code and places properties, and ESLint returns a tuple
- ☝️ ESLint has a name property that is used to calculate configuration file.

And you can even override any of ESLint ⚙️ options with help of config property:

`js
import {safeAlign} from 'eslint-plugin-putout';

const [source, places] = await eslint({
name: 'hello.js',
code: const t = 'hi'\n,
fix: false,
config: [safeAlign],
});
`

If you want to apply 🐊Putout transformations using putout/putout ESLint rule, enable 🐊Putout with the same called but lowercased flag:

`js
import {safeAlign} from 'eslint-plugin-putout';

const [source, places] = await eslint({
name: 'hello.js',
code: const t = 'hi'\n,
fix: true,
putout: true,
config: [safeAlign],
});
`

It is disabled by default, because ESLint always runs after 🐊Putout transformations, so there is no need to traverse tree again.

$3

You can also simplify creating of plugins for ESLint with help of createPlugin.
🐊Putout-based ESLint plugin are highly inspired by Putout Plugins API of Includer.

So it must contain classic 4 methods:

`js
export const report = () => 'debugger statement should not be used';

export const fix = (path) => {
return '';
};

export const include = () => [
'DebuggerStatement',
];

export const filter = (path) => {
return true;
};
`

The main difference with Includer is:

- fix works with text;
- include does not support 🦎PutoutScript;
- there is no exclude;

Take a look at more sophisticated example, rule remove-duplicate-extensions:

`js
const getValue = ({source}) => source?.value;

export const report = () => 'Avoid duplicate extensions in relative imports';
export const include = () => [
'ImportDeclaration',
'ImportExpression',
'ExportAllDeclaration',
'ExportNamedDeclaration',
];

export const fix = ({text}) => {
return text.replace('.js.js', '.js');
};

export const filter = ({node}) => {
const value = getValue(node);
return /\.js\.js/.test(value);
};
`

To use it just add couple lines to your main plugin file:

`js
import {createPlugin} from '@putout/eslint/create-plugin';

const createRule = (a) => ({
[a]: createPlugin(require(./${a})),
});

module.exports.rules = createRule('remove-duplicate-extensions');
`

Or just:

`js
import {createPlugin} from '@putout/eslint/create-plugin';

module.exports.rules = {
'remove-duplicate-extensions': createPlugin(require('./remove-duplicate-extensions')),
};
`

$3

When you need to run ESLint with one plugin (rule), just use lint it will do the thing.

`js
import {lint} from '@putout/eslint/lint';
import {createPlugin} from '@putout/eslint/create-plugin';
import * as removeDebugger from 'remove-debugger';

const [code, places] = lint('debugger', {
fix: true, // default
plugins: [
['remove-debugger', createPlugin(removeDebugger)],
],
});
`

When you want to skip plugins, and just provide options and filename you can:

`js
import {lint} from '@putout/eslint/lint';

const [code, places] = lint('debugger', {
filename: 'index.js',
options: [{
rules: {
semi: 'error',
},
}],
});
``

License

MIT