Add custom method for generating an eslintrc config (#63)

docs/presets/neutrino-lint-base/README.md

@@ -164,6 +164,27 @@ that clearly in your preset.
 For specifics on what options are configured when using this linting base, please
 [view the source](https://github.com/mozilla-neutrino/neutrino-dev/blob/master/packages/neutrino-lint-base/src/index.js).
 
+## eslintrc Config
+
+`neutrino-lint-base` also provides a method for getting the ESLint configuration suitable for use in an eslintrc file.
+Typically this is used for providing hints or fix solutions to the development environment, e.g. IDEs and text editors.
+Doing this requires [creating an instance of the Neutrino API](/api/README.md) and providing the presets uses. If you
+keep this information in `config.presets` in package.json, this should be relatively straightforward. By providing
+all the presets used to Neutrino, you can ensure all the linting options used across all those preset will be merged
+together for your development environment, without the need for copying, duplication, or loss of organization and
+separation.
+
+_Example: Create a .eslintrc.js file in the root of the project._
+
+```js
+// .eslintrc.js
+const Neutrino = require('neutrino');
+const pkg = require('./package.json');
+const api = new Neutrino(pkg.config.presets);
+
+module.exports = api.custom.eslintrc();
+```
+
 ---
 
 ## Contributing

docs/presets/neutrino-preset-airbnb-base/README.md

@@ -199,6 +199,27 @@ module.exports = neutrino => {
 };
 ```
 
+## eslintrc Config
+
+`neutrino-lint-airbnb-base` also provides a method for getting the ESLint configuration suitable for use in an eslintrc
+file. Typically this is used for providing hints or fix solutions to the development environment, e.g. IDEs and text
+editors. Doing this requires [creating an instance of the Neutrino API](/api/README.md) and providing the presets uses.
+If you keep this information in `config.presets` in package.json, this should be relatively straightforward. By
+providing all the presets used to Neutrino, you can ensure all the linting options used across all those preset will be
+merged together for your development environment, without the need for copying, duplication, or loss of organization and
+separation.
+
+_Example: Create a .eslintrc.js file in the root of the project._
+
+```js
+// .eslintrc.js
+const Neutrino = require('neutrino');
+const pkg = require('./package.json');
+const api = new Neutrino(pkg.config.presets);
+
+module.exports = api.custom.eslintrc();
+```
+
 ## Contributing
 
 This preset is part of the [neutrino-dev](https://github.com/mozilla-neutrino/neutrino-dev) repository, a monorepo

packages/neutrino-lint-base/package.json

@@ -16,7 +16,8 @@
     "eslint": "^3.16.1",
     "eslint-loader": "^1.6.1",
     "eslint-plugin-babel": "^4.0.1",
-    "eslint-plugin-import": "^2.2.0"
+    "eslint-plugin-import": "^2.2.0",
+    "lodash.clonedeep": "^4.5.0"
   },
   "peerDependencies": {
     "neutrino": "^4.0.0"

packages/neutrino-lint-base/src/index.js

@@ -1,9 +1,12 @@
+const clone = require('lodash.clonedeep');
 const path = require('path');
 
 const MODULES = path.join(__dirname, '../node_modules');
 const IF_NOT_DEV =  process.env.NODE_ENV !== 'development';
 
-module.exports = ({ config }) => {
+module.exports = neutrino => {
+  const { config } = neutrino;
+
   config
     .module
       .rule('lint')
@@ -37,4 +40,16 @@ module.exports = ({ config }) => {
 
   config.resolve.modules.add(MODULES);
   config.resolveLoader.modules.add(MODULES);
+
+  neutrino.custom.eslintrc = () => {
+    const options = clone(config.module.rule('lint').loaders.get('eslint').options);
+
+    options.extends = options.baseConfig.extends;
+    options.useEslintrc = true;
+    options.env = options.envs.reduce((env, key) => Object.assign(env, { [key]: true }, {}));
+    options.globals = options.globals.reduce((globals, key) => Object.assign(env, { [key]: true }, {}));
+    ['envs', 'baseConfig', 'failOnError', 'emitWarning', 'emitError'].map(method => delete options[method]);
+
+    return options;
+  };
 };

packages/neutrino-lint-base/yarn.lock

@@ -685,6 +685,10 @@ loader-utils@^1.0.2:
     emojis-list "^2.0.0"
     json5 "^0.5.0"
 
+lodash.clonedeep@^4.5.0:
+  version "4.5.0"
+  resolved "https://registry.yarnpkg.com/lodash.clonedeep/-/lodash.clonedeep-4.5.0.tgz#e23f3f9c4f8fbdde872529c1071857a086e5ccef"
+
 lodash.cond@^4.3.0:
   version "4.5.2"
   resolved "https://registry.yarnpkg.com/lodash.cond/-/lodash.cond-4.5.2.tgz#f471a1da486be60f6ab955d17115523dd1d255d5"