eslint-plugin-compat/README.md

Lint browser compatibility of API used

eslint-plugin-compat
=====================
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![demo of plugin usage](https://raw.githubusercontent.com/amilajack/eslint-plugin-compat/master/img/eslint-plugin-compat-demo.gif)

## Goals
 - [x] Allow configuration of target browser/s
 - [x] Use [caniuse](http://caniuse.com) and [@kangax's compat table](http://kangax.github.io/compat-table/es6/) for determining coverage
 - [x] Enable config using `.eslintrc`
 - [x] `browserslist` integration (using `package.json`)

See the [Road Map](https://github.com/amilajack/eslint-plugin-compat/wiki) for more details

## Installation
```bash
npm install --save-dev eslint-plugin-compat
```

Add `"compat"` to `.eslintrc` `"plugins"` section, add `"browser": true` to `"env"`

If you use **typescript**, see [typescript-eslint-parser](https://github.com/eslint/typescript-eslint-parser).
```js
// .eslintrc
{
  // ...
  "env": {
    "browser": true
  },
  "plugins": ["compat"],
  "rules": {
    // ...
    "compat/compat": 2
  }
}
```

## Idea

**Default**
```
 22:  navigator.serviceWorker
                ^^^^^^^^^^^^^ `ServiceWorker` is not supported in IE 11, Edge 15
                               and Safari 8 😢
```

## Targeting Browsers
`eslint-plugin-compat` uses the browserslist configuration in `package.json`

See [ai/browserslist](https://github.com/ai/browserslist) for configuration. Here's some examples:

```js
// Simple configuration (package.json)
{
  // ...
  "browserslist": ["last 1 versions", "not ie <= 8"],
}
```

```js
// Use development and production configurations (package.json)
{
  // ...
  "browserslist": {
    "development": ["last 2 versions"],
    "production": ["last 4 versions"]
  }
}
```

:bulb: You can also define browsers in a [separate browserslist file](https://github.com/ai/browserslist#config-file)

## Adding Polyfills
[See wiki polyfills section](https://github.com/amilajack/eslint-plugin-compat/wiki/Adding-polyfills)

## Inspiration
Toolchains for native platforms, like iOS and Android, have had API linting from the start. It's about time that the web had similar tooling.

This project was inspired by a two hour conversation I had with someone on the experience of web development and if it is terrible or not. The premise they argued was that `x` browser doesn't support `y` feature while `z` browser does. Eventually, I agreed with him on this and checked made this plugin to save web developers from having to memorize browser compatibility of specs.

## Demo
For a minimal demo, see [amilajack/eslint-plugin-compat-demo](https://github.com/amilajack/eslint-plugin-compat-demo)