simplify eslint configs, modernize eslint config for docs js

Author: mdo

.eslintrc.json

@@ -95,12 +95,12 @@ const localRules = {
   'unicorn/no-unused-properties': 'error',
   'unicorn/numeric-separators-style': 'off',
   'unicorn/prefer-array-flat': 'off',
-  'unicorn/prefer-at': 'off',
+  'unicorn/prefer-at': 'error',
   'unicorn/prefer-dom-node-dataset': 'off',
   'unicorn/prefer-global-this': 'off',
   'unicorn/prefer-module': 'off',
   'unicorn/prefer-query-selector': 'off',
-  'unicorn/prefer-spread': 'off',
+  'unicorn/prefer-spread': 'error',
   'unicorn/prefer-string-raw': 'off',
   'unicorn/prefer-string-replace-all': 'off',
   'unicorn/prefer-structured-clone': 'off',
@@ -266,17 +266,14 @@ const eslintConfig = [
     }
   },
 
-  // site/** — browser, script mode, older ecmaVersion
+  // site/** — browser, script mode
   {
     files: ['site/**'],
     languageOptions: {
       globals: {
         ...globals.browser
       },
-      sourceType: 'script',
-      parserOptions: {
-        ecmaVersion: 2019
-      }
+      sourceType: 'script'
     },
     rules: {
       'no-new': 'off',
@@ -296,10 +293,7 @@ const eslintConfig = [
       'site/src/plugins/*.js'
     ],
     languageOptions: {
-      sourceType: 'module',
-      parserOptions: {
-        ecmaVersion: 2020
-      }
+      sourceType: 'module'
     },
     // These files may have eslint-disable directives for the old import plugin
     linterOptions: {
@@ -322,10 +316,7 @@ const eslintConfig = [
       'site/src/assets/examples/sidebars/sidebars.js'
     ],
     languageOptions: {
-      sourceType: 'module',
-      parserOptions: {
-        ecmaVersion: 2020
-      }
+      sourceType: 'module'
     },
     rules: {
       'import/no-unresolved': 'off'

eslint.config.js

@@ -359,7 +359,7 @@ class Combobox extends BaseComponent {
 
       const items = this._getVisibleItems()
       if (items.length > 0) {
-        const target = key === ARROW_DOWN_KEY ? items[0] : items[items.length - 1]
+        const target = key === ARROW_DOWN_KEY ? items[0] : items.at(-1)
         target.focus()
       }
 
@@ -404,7 +404,7 @@ class Combobox extends BaseComponent {
       event.preventDefault()
       const items = this._getVisibleItems()
       if (items.length > 0) {
-        const targetItem = key === HOME_KEY ? items[0] : items[items.length - 1]
+        const targetItem = key === HOME_KEY ? items[0] : items.at(-1)
         targetItem.focus()
       }
 

js/src/combobox.js

@@ -23,7 +23,7 @@ export default {
     // can be removed later when multiple key/instances are fine to be used
     if (!instanceMap.has(key) && instanceMap.size !== 0) {
       // eslint-disable-next-line no-console
-      console.error(`Bootstrap doesn't allow more than one instance per element. Bound instance: ${Array.from(instanceMap.keys())[0]}.`)
+      console.error(`Bootstrap doesn't allow more than one instance per element. Bound instance: ${[...instanceMap.keys()][0]}.`)
       return
     }
 

js/src/dom/data.js

@@ -34,15 +34,15 @@ const getSelector = element => {
 
 const SelectorEngine = {
   find(selector, element = document.documentElement) {
-    return [].concat(...Element.prototype.querySelectorAll.call(element, selector))
+    return [...Element.prototype.querySelectorAll.call(element, selector)]
   },
 
   findOne(selector, element = document.documentElement) {
     return Element.prototype.querySelector.call(element, selector)
   },
 
   children(element, selector) {
-    return [].concat(...element.children).filter(child => child.matches(selector))
+    return [...element.children].filter(child => child.matches(selector))
   },
 
   parents(element, selector) {

js/src/dom/selector-engine.js

@@ -186,7 +186,7 @@ class Menu extends BaseComponent {
     this._createFloating()
 
     if ('ontouchstart' in document.documentElement && !this._parent.closest(SELECTOR_NAVBAR_NAV)) {
-      for (const element of [].concat(...document.body.children)) {
+      for (const element of document.body.children) {
         EventHandler.on(element, 'mouseover', noop)
       }
     }
@@ -249,7 +249,7 @@ class Menu extends BaseComponent {
     this._closeAllSubmenus()
 
     if ('ontouchstart' in document.documentElement) {
-      for (const element of [].concat(...document.body.children)) {
+      for (const element of document.body.children) {
         EventHandler.off(element, 'mouseover', noop)
       }
     }
@@ -837,7 +837,7 @@ class Menu extends BaseComponent {
         .filter(element => isVisible(element))
 
       if (items.length) {
-        const targetItem = key === HOME_KEY ? items[0] : items[items.length - 1]
+        const targetItem = key === HOME_KEY ? items[0] : items.at(-1)
         targetItem.focus()
       }