[Tooling] Expand browsers target while keeping Polyfills under control (#709)

* expand browsers target

* add eslint-plugin-compat

* sort polyfils

* adjust readme

* add polyfills sync check action

* only build js

* trim

* add Element.prototype.closest

* add closest to demo links

* fix ignore

.browserslistrc

@@ -1,2 +1 @@
-> 5%
-IE 11
+> 1%

.eslintrc → .eslintrc.json

@@ -2,13 +2,18 @@
   "parserOptions": {
     "ecmaVersion": 2020
   },
-  "extends": ["airbnb-base", "plugin:prettier/recommended"],
+  "extends": [
+    "airbnb-base",
+    "plugin:prettier/recommended",
+    "plugin:compat/recommended"
+  ],
   "plugins": ["prettier"],
   "env": {
     "es6": true,
     "browser": true
   },
   "rules": {
+    "import/prefer-default-export": "off",
     "import/no-extraneous-dependencies": [
       "error",
       {
@@ -41,7 +46,8 @@
         "mocha": true
       },
       "rules": {
-        "no-restricted-syntax": "off"
+        "no-restricted-syntax": "off",
+        "compat/compat": "off"
       }
     },
     {
@@ -51,5 +57,18 @@
         "cypress/globals": true
       }
     }
-  ]
+  ],
+  "settings": {
+    "polyfills": [
+      "Array.from",
+      "Array.prototype.find",
+      "Array.prototype.includes",
+      "Symbol",
+      "Symbol.iterator",
+      "Object.assign",
+      "CustomEvent",
+      "Element.prototype.classList",
+      "Element.prototype.closest"
+    ]
+  }
 }

.github/actions-scripts/polyfills-sync.js

@@ -0,0 +1,14 @@
+const { readFileSync } = require('fs');
+const path = require('path');
+const assert = require('assert');
+
+const readme = readFileSync(path.resolve(__dirname, '../../README.md'), 'utf8');
+
+const polyfillsFromDocs = /^```polyfills\s*\n([^`]+)\n^```/m
+  .exec(readme)[1]
+  .split('\n')
+  .map(v => v.trim())
+  .sort();
+// @ts-ignore
+const polyfillsFromSettings = require('../../.eslintrc.json').settings.polyfills.sort();
+assert.deepStrictEqual(polyfillsFromDocs, polyfillsFromSettings);

.github/workflows/lint.yml

@@ -31,3 +31,8 @@ jobs:
           if [[ -z $(sed -e 's/[[:space:]]*$//' <<<${CHANGED_JS}) ]]; then CHANGED_JS="src/scripts"; fi
           echo $CHANGED_JS
           node node_modules/eslint/bin/eslint.js $CHANGED_JS
+
+      - name: Lint JS bundle
+        run: |
+          npm run js:build
+          npx eslint --no-ignore ./public/assets/scripts/*.js

.github/workflows/polyfills-sync.yml

@@ -0,0 +1,23 @@
+name: Polyfills documentation
+
+on:
+  pull_request:
+    paths:
+      - 'README.md'
+      - '.browserslistrc'
+      - '.eslintrc.json'
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+        with:
+          fetch-depth: 1
+
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 12
+
+      - name: Check Polyfills documentation and settings sync
+        run: node .github/actions-scripts/polyfills-sync.js

README.md

@@ -1029,29 +1029,30 @@ example.setChoiceByValue('Two'); // Choice with value of 'Two' has now been sele
 
 ## Browser compatibility
 
-Choices is compiled using [Babel](https://babeljs.io/) to enable support for [ES5 browsers](http://caniuse.com/#feat=es5). If you need to support a browser that does not support one of the features listed below, I suggest including a polyfill from the very good [polyfill.io](https://cdn.polyfill.io/v2/docs/):
+Choices is compiled using [Babel](https://babeljs.io/) targeting browsers [with more that 1% of global usage](https://github.com/jshjohnson/Choices/blob/master/.browserslistrc) and expecting that features [listed below](https://github.com/jshjohnson/Choices/blob/master/.eslintrc.json#L62) are available or polyfilled in browser.
+You may see exact list of target browsers by running `npx browserslist` withing this repository folder.
+If you need to support a browser that does not have one of the features listed below,
+I suggest including a polyfill from the very good [polyfill.io](https://polyfill.io/v3/):
 
 **Polyfill example used for the demo:**
 
 ```html
-<script src="https://cdn.polyfill.io/v2/polyfill.js?features=es5,fetch,Element.prototype.classList,requestAnimationFrame,Node.insertBefore,Node.firstChild,CustomEvent"></script>
+<script src="https://cdn.polyfill.io/v3/polyfill.min.js?features=es5,es6,fetch,Array.prototype.includes,CustomEvent,Element.prototype.closest"></script>
 ```
 
 **Features used in Choices:**
 
-- Array.prototype.forEach
-- Array.prototype.map
-- Array.prototype.find
-- Array.prototype.some
-- Array.prototype.includes
-- Array.from
-- Array.prototype.reduce
-- Array.prototype.indexOf
-- Object.assign
-- Element.prototype.classList
-- Element.prototype.closest
-- window.requestAnimationFrame
-- CustomEvent
+```polyfills
+Array.from
+Array.prototype.find
+Array.prototype.includes
+Symbol
+Symbol.iterator
+Object.assign
+CustomEvent
+Element.prototype.classList
+Element.prototype.closest
+```
 
 ## Development
 

package-lock.json

@@ -753,6 +753,15 @@
         "source-map-support": "^0.5.9"
       }
     },
+    "@babel/runtime": {
+      "version": "7.6.3",
+      "resolved": "https://registry.npmjs.org/@babel/runtime/-/runtime-7.6.3.tgz",
+      "integrity": "sha512-kq6anf9JGjW8Nt5rYfEuGRaEAaH1mkv3Bbu6rYvLOpPh/RusSJXuKPEAoZ7L7gybZkchE8+NV5g9vKF4AGAtsA==",
+      "dev": true,
+      "requires": {
+        "regenerator-runtime": "^0.13.2"
+      }
+    },
     "@babel/template": {
       "version": "7.6.0",
       "resolved": "https://registry.npmjs.org/@babel/template/-/template-7.6.0.tgz",
@@ -1539,6 +1548,12 @@
       "integrity": "sha1-WWZ/QfrdTyDMvCu5a41Pf3jsA2c=",
       "dev": true
     },
+    "ast-metadata-inferer": {
+      "version": "0.1.1",
+      "resolved": "https://registry.npmjs.org/ast-metadata-inferer/-/ast-metadata-inferer-0.1.1.tgz",
+      "integrity": "sha512-hc9w8Qrgg9Lf9iFcZVhNjUnhrd2BBpTlyCnegPVvCe6O0yMrF57a6Cmh7k+xUsfUOMh9wajOL5AsGOBNEyTCcw==",
+      "dev": true
+    },
     "astral-regex": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/astral-regex/-/astral-regex-1.0.0.tgz",
@@ -2214,6 +2229,12 @@
         }
       }
     },
+    "caniuse-db": {
+      "version": "1.0.30001004",
+      "resolved": "https://registry.npmjs.org/caniuse-db/-/caniuse-db-1.0.30001004.tgz",
+      "integrity": "sha512-VBTptWLoxsIhIGFZOEvtHhdRyhh+6JARUnVy2debGRNmrKfunVAa9cRuAvOnrQk4z/SDiNm5S2d6h32eIHZMoA==",
+      "dev": true
+    },
     "caniuse-lite": {
       "version": "1.0.30001002",
       "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001002.tgz",
@@ -3882,6 +3903,29 @@
         }
       }
     },
+    "eslint-plugin-compat": {
+      "version": "3.3.0",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-compat/-/eslint-plugin-compat-3.3.0.tgz",
+      "integrity": "sha512-QCgYy3pZ+zH10dkBJus1xER0359h1UhJjufhQRqp9Owm6BEoLZeSqxf2zINwL1OGao9Yc96xPYIW3nQj5HUryg==",
+      "dev": true,
+      "requires": {
+        "@babel/runtime": "^7.4.5",
+        "ast-metadata-inferer": "^0.1.1",
+        "browserslist": "^4.6.3",
+        "caniuse-db": "^1.0.30000977",
+        "lodash.memoize": "4.1.2",
+        "mdn-browser-compat-data": "^0.0.84",
+        "semver": "^6.1.2"
+      },
+      "dependencies": {
+        "semver": {
+          "version": "6.3.0",
+          "resolved": "https://registry.npmjs.org/semver/-/semver-6.3.0.tgz",
+          "integrity": "sha512-b39TBaTSfV6yBrapU89p5fKekE2m/NwnDocOVruQFS1/veMgdzuPcnOM34M6CwxW8jH/lxEa5rBoDeUwu5HHTw==",
+          "dev": true
+        }
+      }
+    },
     "eslint-plugin-cypress": {
       "version": "2.7.0",
       "resolved": "https://registry.npmjs.org/eslint-plugin-cypress/-/eslint-plugin-cypress-2.7.0.tgz",
@@ -7971,6 +8015,12 @@
       "integrity": "sha1-+wMJF/hqMTTlvJvsDWngAT3f7bI=",
       "dev": true
     },
+    "lodash.memoize": {
+      "version": "4.1.2",
+      "resolved": "https://registry.npmjs.org/lodash.memoize/-/lodash.memoize-4.1.2.tgz",
+      "integrity": "sha1-vMbEmkKihA7Zl/Mj6tpezRguC/4=",
+      "dev": true
+    },
     "lodash.once": {
       "version": "4.1.1",
       "resolved": "https://registry.npmjs.org/lodash.once/-/lodash.once-4.1.1.tgz",
@@ -8099,6 +8149,15 @@
         "safe-buffer": "^5.1.2"
       }
     },
+    "mdn-browser-compat-data": {
+      "version": "0.0.84",
+      "resolved": "https://registry.npmjs.org/mdn-browser-compat-data/-/mdn-browser-compat-data-0.0.84.tgz",
+      "integrity": "sha512-fAznuGNaQMQiWLVf+gyp33FaABTglYWqMT7JqvH+4RZn2UQPD12gbMqxwP9m0lj8AAbNpu5/kD6n4Ox1SOffpw==",
+      "dev": true,
+      "requires": {
+        "extend": "3.0.2"
+      }
+    },
     "mdn-data": {
       "version": "2.0.4",
       "resolved": "https://registry.npmjs.org/mdn-data/-/mdn-data-2.0.4.tgz",
@@ -11391,6 +11450,12 @@
         "regenerate": "^1.4.0"
       }
     },
+    "regenerator-runtime": {
+      "version": "0.13.3",
+      "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.13.3.tgz",
+      "integrity": "sha512-naKIZz2GQ8JWh///G7L3X6LaQUAMp2lvb1rvwwsURe/VXwD6VMfr+/1NuNw3ag8v2kY1aQ/go5SNn79O9JU7yw==",
+      "dev": true
+    },
     "regenerator-transform": {
       "version": "0.14.1",
       "resolved": "https://registry.npmjs.org/regenerator-transform/-/regenerator-transform-0.14.1.tgz",

package.json

@@ -67,6 +67,7 @@
     "eslint-config-airbnb-base": "^14.0.0",
     "eslint-config-prettier": "^6.4.0",
     "eslint-loader": "^3.0.2",
+    "eslint-plugin-compat": "3.3.0",
     "eslint-plugin-cypress": "^2.7.0",
     "eslint-plugin-import": "^2.18.2",
     "eslint-plugin-prettier": "^3.1.1",

public/assets/scripts/.eslintrc.js

@@ -0,0 +1,24 @@
+
+// get polyfill settings from top level config
+// @ts-ignore
+const { settings } = require('../../../.eslintrc.json');
+
+// Adding non-polyfilable Symbol-related functions as they are most probably
+// behind the flag
+
+settings.polyfills.push('Symbol.toStringTag', 'Symbol.for', 'Object.getOwnPropertySymbols', 'Object.getOwnPropertyDescriptors')
+
+module.exports = /** @type {import('eslint').Linter.Config} */({
+  root: true,
+  extends: [
+    "plugin:compat/recommended"
+  ],
+  parserOptions: {
+    // ensure that it's compatible with ES5 browsers, so, no `const`, etc
+    ecmaVersion: 5
+  },
+  env: {
+    browser: true
+  },
+  settings
+})

public/index.html

@@ -47,7 +47,7 @@
     <!-- End ignore these -->
 
     <!-- Optional includes -->
-    <script src="https://polyfill.io/v3/polyfill.min.js?features=es5%2Ces6%2CArray.prototype.includes%2Cfetch%2CCustomEvent"></script>
+    <script src="https://polyfill.io/v3/polyfill.min.js?features=es5%2Ces6%2CArray.prototype.includes%2Cfetch%2CCustomEvent%2CElement.prototype.closest"></script>
     <!-- End optional includes -->
 
     <!-- Choices includes -->

src/scripts/actions/general.js

@@ -1,5 +1,3 @@
-/* eslint-disable import/prefer-default-export */
-
 export const setIsLoading = isLoading => ({
   type: 'SET_IS_LOADING',
   isLoading,

src/scripts/actions/groups.js

@@ -1,6 +1,5 @@
 import { ACTION_TYPES } from '../constants';
 
-/* eslint-disable import/prefer-default-export */
 export const addGroup = (value, id, active, disabled) => ({
   type: ACTION_TYPES.ADD_GROUP,
   value,