Use Babel and ES6 in docs JS files (#31607)

* Pass docs js through Babel

* Use ES6 in docs js

* Only run babel on src files

* Allow babel in Hugo

* Update scripts.html

* Inherit from the root .eslintrc.json

* Use `Array.from`

* Drop Babel from docs

* Prefer template

* replace IIFE with arrow functions

Co-authored-by: XhmikosR <xhmikosr@gmail.com>
Co-authored-by: GeoSot <geo.sotis@gmail.com>

11 files changed, 122 insertions, 167 deletions

diff --git a/site/.eslintrc.json b/site/.eslintrc.json
index 56b3b40404..5bdb283e2d 100644
--- a/site/.eslintrc.json
+++ b/site/.eslintrc.json
@@ -1,61 +1,17 @@
 {
-  "root": true,
+  "env": {
+    "browser": true,
+    "node": false
+  },
   "parserOptions": {
-    "ecmaVersion": 5,
     "sourceType": "script"
   },
-  "extends": [
-    "plugin:unicorn/recommended",
-    "xo",
-    "xo/browser"
-  ],
+  "extends": "../.eslintrc.json",
   "rules": {
-    "arrow-body-style": "off",
-    "capitalized-comments": "off",
-    "comma-dangle": [
-      "error",
-      "never"
-    ],
-    "indent": [
-      "error",
-      2,
-      {
-        "MemberExpression": "off",
-        "SwitchCase": 1
-      }
-    ],
-    "multiline-ternary": [
-      "error",
-      "always-multiline"
-    ],
-    "no-negated-condition": "off",
     "no-new": "off",
-    "no-var": "off",
-    "object-curly-spacing": [
-      "error",
-      "always"
-    ],
-    "object-shorthand": "off",
-    "operator-linebreak": [
-      "error",
-      "after"
-    ],
-    "prefer-arrow-callback": "off",
-    "prefer-destructuring": "off",
-    "semi": [
-      "error",
-      "never"
-    ],
+    "prefer-template": "error",
     "strict": "error",
     "unicorn/no-array-for-each": "off",
-    "unicorn/no-array-method-this-argument": "off",
-    "unicorn/no-for-loop": "off",
-    "unicorn/no-null": "off",
-    "unicorn/numeric-separators-style": "off",
-    "unicorn/prefer-array-flat": "off",
-    "unicorn/prefer-dom-node-dataset": "off",
-    "unicorn/prefer-module": "off",
-    "unicorn/prefer-query-selector": "off",
-    "unicorn/prevent-abbreviations": "off"
+    "unicorn/numeric-separators-style": "off"
   }
 }
diff --git a/site/assets/js/application.js b/site/assets/js/application.js
index fa1fba00d9..c14dc57c22 100644
--- a/site/assets/js/application.js
+++ b/site/assets/js/application.js
@@ -12,117 +12,117 @@
 
 /* global ClipboardJS: false, bootstrap: false */
 
-(function () {
+(() => {
   'use strict'
 
   // Tooltip and popover demos
   document.querySelectorAll('.tooltip-demo')
-    .forEach(function (tooltip) {
+    .forEach(tooltip => {
       new bootstrap.Tooltip(tooltip, {
         selector: '[data-bs-toggle="tooltip"]'
       })
     })
 
   document.querySelectorAll('[data-bs-toggle="popover"]')
-    .forEach(function (popover) {
+    .forEach(popover => {
       new bootstrap.Popover(popover)
     })
 
-  var toastPlacement = document.getElementById('toastPlacement')
+  const toastPlacement = document.getElementById('toastPlacement')
   if (toastPlacement) {
     document.getElementById('selectToastPlacement').addEventListener('change', function () {
       if (!toastPlacement.dataset.originalClass) {
         toastPlacement.dataset.originalClass = toastPlacement.className
       }
 
-      toastPlacement.className = toastPlacement.dataset.originalClass + ' ' + this.value
+      toastPlacement.className = `${toastPlacement.dataset.originalClass} ${this.value}`
     })
   }
 
   document.querySelectorAll('.bd-example .toast')
-    .forEach(function (toastNode) {
-      var toast = new bootstrap.Toast(toastNode, {
+    .forEach(toastNode => {
+      const toast = new bootstrap.Toast(toastNode, {
         autohide: false
       })
 
       toast.show()
     })
 
-  var toastTrigger = document.getElementById('liveToastBtn')
-  var toastLiveExample = document.getElementById('liveToast')
+  const toastTrigger = document.getElementById('liveToastBtn')
+  const toastLiveExample = document.getElementById('liveToast')
   if (toastTrigger) {
-    toastTrigger.addEventListener('click', function () {
-      var toast = new bootstrap.Toast(toastLiveExample)
+    toastTrigger.addEventListener('click', () => {
+      const toast = new bootstrap.Toast(toastLiveExample)
 
       toast.show()
     })
   }
 
-  var alertPlaceholder = document.getElementById('liveAlertPlaceholder')
-  var alertTrigger = document.getElementById('liveAlertBtn')
+  const alertPlaceholder = document.getElementById('liveAlertPlaceholder')
+  const alertTrigger = document.getElementById('liveAlertBtn')
 
   function alert(message, type) {
-    var wrapper = document.createElement('div')
-    wrapper.innerHTML = '<div class="alert alert-' + type + ' alert-dismissible" role="alert">' + message + '<button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button></div>'
+    const wrapper = document.createElement('div')
+    wrapper.innerHTML = `<div class="alert alert-${type} alert-dismissible" role="alert">${message}<button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button></div>`
 
     alertPlaceholder.append(wrapper)
   }
 
   if (alertTrigger) {
-    alertTrigger.addEventListener('click', function () {
+    alertTrigger.addEventListener('click', () => {
       alert('Nice, you triggered this alert message!', 'success')
     })
   }
 
   // Demos within modals
   document.querySelectorAll('.tooltip-test')
-    .forEach(function (tooltip) {
+    .forEach(tooltip => {
       new bootstrap.Tooltip(tooltip)
     })
 
   document.querySelectorAll('.popover-test')
-    .forEach(function (popover) {
+    .forEach(popover => {
       new bootstrap.Popover(popover)
     })
 
   // Indeterminate checkbox example
   document.querySelectorAll('.bd-example-indeterminate [type="checkbox"]')
-    .forEach(function (checkbox) {
+    .forEach(checkbox => {
       checkbox.indeterminate = true
     })
 
   // Disable empty links in docs examples
   document.querySelectorAll('.bd-content [href="#"]')
-    .forEach(function (link) {
-      link.addEventListener('click', function (event) {
+    .forEach(link => {
+      link.addEventListener('click', event => {
         event.preventDefault()
       })
     })
 
   // Modal relatedTarget demo
-  var exampleModal = document.getElementById('exampleModal')
+  const exampleModal = document.getElementById('exampleModal')
   if (exampleModal) {
-    exampleModal.addEventListener('show.bs.modal', function (event) {
+    exampleModal.addEventListener('show.bs.modal', event => {
       // Button that triggered the modal
-      var button = event.relatedTarget
+      const button = event.relatedTarget
       // Extract info from data-bs-* attributes
-      var recipient = button.getAttribute('data-bs-whatever')
+      const recipient = button.getAttribute('data-bs-whatever')
 
       // Update the modal's content.
-      var modalTitle = exampleModal.querySelector('.modal-title')
-      var modalBodyInput = exampleModal.querySelector('.modal-body input')
+      const modalTitle = exampleModal.querySelector('.modal-title')
+      const modalBodyInput = exampleModal.querySelector('.modal-body input')
 
-      modalTitle.textContent = 'New message to ' + recipient
+      modalTitle.textContent = `New message to ${recipient}`
       modalBodyInput.value = recipient
     })
   }
 
   // Insert copy to clipboard button before .highlight
-  var btnTitle = 'Copy to clipboard'
-  var btnEdit = 'Edit on StackBlitz'
-  var btnHtml = '<div class="bd-clipboard"><button type="button" class="btn-clipboard">Copy</button></div>'
+  const btnTitle = 'Copy to clipboard'
+  const btnEdit = 'Edit on StackBlitz'
+  const btnHtml = '<div class="bd-clipboard"><button type="button" class="btn-clipboard">Copy</button></div>'
   document.querySelectorAll('div.highlight')
-    .forEach(function (element) {
+    .forEach(element => {
       element.insertAdjacentHTML('beforebegin', btnHtml)
     })
 
@@ -132,10 +132,10 @@
    * @param {string} title
    */
   function snippetButtonTooltip(selector, title) {
-    document.querySelectorAll(selector).forEach(function (btn) {
-      var tooltipBtn = new bootstrap.Tooltip(btn, { title: title })
+    document.querySelectorAll(selector).forEach(btn => {
+      const tooltipBtn = new bootstrap.Tooltip(btn, { title })
 
-      btn.addEventListener('mouseleave', function () {
+      btn.addEventListener('mouseleave', () => {
         // Explicitly hide tooltip, since after clicking it remains
         // focused (as it's a button), so tooltip would otherwise
         // remain visible until focus is moved away
@@ -147,29 +147,29 @@
   snippetButtonTooltip('.btn-clipboard', btnTitle)
   snippetButtonTooltip('.btn-edit', btnEdit)
 
-  var clipboard = new ClipboardJS('.btn-clipboard', {
-    target: function (trigger) {
+  const clipboard = new ClipboardJS('.btn-clipboard', {
+    target(trigger) {
       return trigger.parentNode.nextElementSibling
     }
   })
 
-  clipboard.on('success', function (event) {
-    var tooltipBtn = bootstrap.Tooltip.getInstance(event.trigger)
+  clipboard.on('success', event => {
+    const tooltipBtn = bootstrap.Tooltip.getInstance(event.trigger)
 
     tooltipBtn.setContent({ '.tooltip-inner': 'Copied!' })
-    event.trigger.addEventListener('hidden.bs.tooltip', function () {
+    event.trigger.addEventListener('hidden.bs.tooltip', () => {
       tooltipBtn.setContent({ '.tooltip-inner': btnTitle })
     }, { once: true })
     event.clearSelection()
   })
 
-  clipboard.on('error', function (event) {
-    var modifierKey = /mac/i.test(navigator.userAgent) ? '\u2318' : 'Ctrl-'
-    var fallbackMsg = 'Press ' + modifierKey + 'C to copy'
-    var tooltipBtn = bootstrap.Tooltip.getInstance(event.trigger)
+  clipboard.on('error', event => {
+    const modifierKey = /mac/i.test(navigator.userAgent) ? '\u2318' : 'Ctrl-'
+    const fallbackMsg = `Press ${modifierKey}C to copy`
+    const tooltipBtn = bootstrap.Tooltip.getInstance(event.trigger)
 
     tooltipBtn.setContent({ '.tooltip-inner': fallbackMsg })
-    event.trigger.addEventListener('hidden.bs.tooltip', function () {
+    event.trigger.addEventListener('hidden.bs.tooltip', () => {
       tooltipBtn.setContent({ '.tooltip-inner': btnTitle })
     }, { once: true })
   })
diff --git a/site/assets/js/search.js b/site/assets/js/search.js
index d88263d3f3..15197bfd9a 100644
--- a/site/assets/js/search.js
+++ b/site/assets/js/search.js
@@ -2,18 +2,18 @@
 // IT'S ALL JUST JUNK FOR OUR DOCS!
 // ++++++++++++++++++++++++++++++++++++++++++
 
-(function () {
+(() => {
   'use strict'
 
-  var inputElement = document.getElementById('search-input')
+  const inputElement = document.getElementById('search-input')
 
   if (!window.docsearch || !inputElement) {
     return
   }
 
-  var siteDocsVersion = inputElement.getAttribute('data-bd-docs-version')
+  const siteDocsVersion = inputElement.getAttribute('data-bd-docs-version')
 
-  document.addEventListener('keydown', function (event) {
+  document.addEventListener('keydown', event => {
     if (event.ctrlKey && event.key === '/') {
       event.preventDefault()
       inputElement.focus()
@@ -25,11 +25,11 @@
     indexName: 'bootstrap',
     inputSelector: '#search-input',
     algoliaOptions: {
-      facetFilters: ['version:' + siteDocsVersion]
+      facetFilters: [`version:${siteDocsVersion}`]
     },
-    transformData: function (hits) {
-      return hits.map(function (hit) {
-        var liveUrl = 'https://getbootstrap.com/'
+    transformData(hits) {
+      return hits.map(hit => {
+        const liveUrl = 'https://getbootstrap.com/'
 
         hit.url = window.location.origin.startsWith(liveUrl) ?
           // On production, return the result as is
diff --git a/site/content/docs/5.1/examples/cheatsheet/cheatsheet.js b/site/content/docs/5.1/examples/cheatsheet/cheatsheet.js
index 0a50258b92..e25a89e75d 100644
--- a/site/content/docs/5.1/examples/cheatsheet/cheatsheet.js
+++ b/site/content/docs/5.1/examples/cheatsheet/cheatsheet.js
@@ -1,24 +1,24 @@
 /* global bootstrap: false */
 
-(function () {
+(() => {
   'use strict'
 
   // Tooltip and popover demos
   document.querySelectorAll('.tooltip-demo')
-    .forEach(function (tooltip) {
+    .forEach(tooltip => {
       new bootstrap.Tooltip(tooltip, {
         selector: '[data-bs-toggle="tooltip"]'
       })
     })
 
   document.querySelectorAll('[data-bs-toggle="popover"]')
-    .forEach(function (popover) {
+    .forEach(popover => {
       new bootstrap.Popover(popover)
     })
 
   document.querySelectorAll('.toast')
-    .forEach(function (toastNode) {
-      var toast = new bootstrap.Toast(toastNode, {
+    .forEach(toastNode => {
+      const toast = new bootstrap.Toast(toastNode, {
         autohide: false
       })
 
@@ -27,27 +27,27 @@
 
   // Disable empty links and submit buttons
   document.querySelectorAll('[href="#"], [type="submit"]')
-    .forEach(function (link) {
-      link.addEventListener('click', function (event) {
+    .forEach(link => {
+      link.addEventListener('click', event => {
         event.preventDefault()
       })
     })
 
   function setActiveItem() {
-    var hash = window.location.hash
+    const { hash } = window.location
 
     if (hash === '') {
       return
     }
 
-    var link = document.querySelector('.bd-aside a[href="' + hash + '"]')
+    const link = document.querySelector(`.bd-aside a[href="${hash}"]`)
 
     if (!link) {
       return
     }
 
-    var active = document.querySelector('.bd-aside .active')
-    var parent = link.parentNode.parentNode.previousElementSibling
+    const active = document.querySelector('.bd-aside .active')
+    const parent = link.parentNode.parentNode.previousElementSibling
 
     link.classList.add('active')
 
@@ -59,7 +59,7 @@
       return
     }
 
-    var expanded = active.parentNode.parentNode.previousElementSibling
+    const expanded = active.parentNode.parentNode.previousElementSibling
 
     active.classList.remove('active')
 
diff --git a/site/content/docs/5.1/examples/checkout/form-validation.js b/site/content/docs/5.1/examples/checkout/form-validation.js
index f8fd583de4..30ea0aa6b1 100644
--- a/site/content/docs/5.1/examples/checkout/form-validation.js
+++ b/site/content/docs/5.1/examples/checkout/form-validation.js
@@ -1,20 +1,19 @@
 // Example starter JavaScript for disabling form submissions if there are invalid fields
-(function () {
+(() => {
   'use strict'
 
   // Fetch all the forms we want to apply custom Bootstrap validation styles to
-  var forms = document.querySelectorAll('.needs-validation')
+  const forms = document.querySelectorAll('.needs-validation')
 
   // Loop over them and prevent submission
-  Array.prototype.slice.call(forms)
-    .forEach(function (form) {
-      form.addEventListener('submit', function (event) {
-        if (!form.checkValidity()) {
-          event.preventDefault()
-          event.stopPropagation()
-        }
+  Array.from(forms).forEach(form => {
+    form.addEventListener('submit', event => {
+      if (!form.checkValidity()) {
+        event.preventDefault()
+        event.stopPropagation()
+      }
 
-        form.classList.add('was-validated')
-      }, false)
-    })
+      form.classList.add('was-validated')
+    }, false)
+  })
 })()
diff --git a/site/content/docs/5.1/examples/dashboard-rtl/dashboard.js b/site/content/docs/5.1/examples/dashboard-rtl/dashboard.js
index 7831fa9d09..96e0895bf2 100644
--- a/site/content/docs/5.1/examples/dashboard-rtl/dashboard.js
+++ b/site/content/docs/5.1/examples/dashboard-rtl/dashboard.js
@@ -1,14 +1,14 @@
 /* globals Chart:false, feather:false */
 
-(function () {
+(() => {
   'use strict'
 
   feather.replace({ 'aria-hidden': 'true' })
 
   // Graphs
-  var ctx = document.getElementById('myChart')
+  const ctx = document.getElementById('myChart')
   // eslint-disable-next-line no-unused-vars
-  var myChart = new Chart(ctx, {
+  const myChart = new Chart(ctx, {
     type: 'line',
     data: {
       labels: [
diff --git a/site/content/docs/5.1/examples/dashboard/dashboard.js b/site/content/docs/5.1/examples/dashboard/dashboard.js
index 7c2402ae2e..e1379758b2 100644
--- a/site/content/docs/5.1/examples/dashboard/dashboard.js
+++ b/site/content/docs/5.1/examples/dashboard/dashboard.js
@@ -1,14 +1,14 @@
 /* globals Chart:false, feather:false */
 
-(function () {
+(() => {
   'use strict'
 
   feather.replace({ 'aria-hidden': 'true' })
 
   // Graphs
-  var ctx = document.getElementById('myChart')
+  const ctx = document.getElementById('myChart')
   // eslint-disable-next-line no-unused-vars
-  var myChart = new Chart(ctx, {
+  const myChart = new Chart(ctx, {
     type: 'line',
     data: {
       labels: [
diff --git a/site/content/docs/5.1/examples/offcanvas-navbar/offcanvas.js b/site/content/docs/5.1/examples/offcanvas-navbar/offcanvas.js
index 91103b1c4e..b97a171648 100644
--- a/site/content/docs/5.1/examples/offcanvas-navbar/offcanvas.js
+++ b/site/content/docs/5.1/examples/offcanvas-navbar/offcanvas.js
@@ -1,7 +1,7 @@
-(function () {
+(() => {
   'use strict'
 
-  document.querySelector('#navbarSideCollapse').addEventListener('click', function () {
+  document.querySelector('#navbarSideCollapse').addEventListener('click', () => {
     document.querySelector('.offcanvas-collapse').classList.toggle('open')
   })
 })()
diff --git a/site/content/docs/5.1/examples/sidebars/sidebars.js b/site/content/docs/5.1/examples/sidebars/sidebars.js
index d00bc0db16..4075f1f155 100644
--- a/site/content/docs/5.1/examples/sidebars/sidebars.js
+++ b/site/content/docs/5.1/examples/sidebars/sidebars.js
@@ -1,8 +1,8 @@
 /* global bootstrap: false */
-(function () {
+(() => {
   'use strict'
-  var tooltipTriggerList = Array.prototype.slice.call(document.querySelectorAll('[data-bs-toggle="tooltip"]'))
-  tooltipTriggerList.forEach(function (tooltipTriggerEl) {
+  const tooltipTriggerList = Array.from(document.querySelectorAll('[data-bs-toggle="tooltip"]'))
+  tooltipTriggerList.forEach(tooltipTriggerEl => {
     new bootstrap.Tooltip(tooltipTriggerEl)
   })
 })()
diff --git a/site/layouts/partials/scripts.html b/site/layouts/partials/scripts.html
index 47cc55dff7..2b70521f5d 100644
--- a/site/layouts/partials/scripts.html
+++ b/site/layouts/partials/scripts.html
@@ -23,19 +23,16 @@
 {{ if eq .Page.Layout "docs" -}}
 <script>
   // Open in StackBlitz logic
-  document.querySelectorAll('.btn-edit')
-    .forEach(function (btn) {
-      btn.addEventListener('click', function (event) {
-        var htmlSnippet = event.target.closest('.bd-edit').previousSibling.innerHTML
+  document.querySelectorAll('.btn-edit').forEach(btn => {
+    btn.addEventListener('click', event => {
+      const htmlSnippet = event.target.closest('.bd-edit').previousSibling.innerHTML
 
-        StackBlitzSDK.openBootstrapSnippet(htmlSnippet)
-      })
+      StackBlitzSDK.openBootstrapSnippet(htmlSnippet)
     })
+  })
 
-  StackBlitzSDK.openBootstrapSnippet = function(snippet) {
-    var project = {
-        files: {
-          'index.html': `<!doctype html>
+  StackBlitzSDK.openBootstrapSnippet = snippet => {
+    const markup = `<!doctype html>
 <html lang="en">
   <head>
     <meta charset="utf-8">
@@ -52,12 +49,16 @@ ${snippet.replace(/^/gm, '    ')}
     <${'script'} src="{{ .Site.Params.cdn.js_bundle }}"></${'script'}>
   </body>
 </html>`
-        },
-        title: 'Bootstrap Example',
-        description: 'Official example from ' + window.location.href,
-        template: 'html',
-        tags: ['bootstrap']
-      }
+
+    const project = {
+      files: {
+        'index.html': markup
+      },
+      title: 'Bootstrap Example',
+      description: `Official example from ${window.location.href}`,
+      template: 'html',
+      tags: ['bootstrap']
+    }
 
     StackBlitzSDK.openProject(project, { openFile: 'index.html' })
   }
diff --git a/site/static/docs/5.1/assets/js/validate-forms.js b/site/static/docs/5.1/assets/js/validate-forms.js
index f8fd583de4..30ea0aa6b1 100644
--- a/site/static/docs/5.1/assets/js/validate-forms.js
+++ b/site/static/docs/5.1/assets/js/validate-forms.js
@@ -1,20 +1,19 @@
 // Example starter JavaScript for disabling form submissions if there are invalid fields
-(function () {
+(() => {
   'use strict'
 
   // Fetch all the forms we want to apply custom Bootstrap validation styles to
-  var forms = document.querySelectorAll('.needs-validation')
+  const forms = document.querySelectorAll('.needs-validation')
 
   // Loop over them and prevent submission
-  Array.prototype.slice.call(forms)
-    .forEach(function (form) {
-      form.addEventListener('submit', function (event) {
-        if (!form.checkValidity()) {
-          event.preventDefault()
-          event.stopPropagation()
-        }
+  Array.from(forms).forEach(form => {
+    form.addEventListener('submit', event => {
+      if (!form.checkValidity()) {
+        event.preventDefault()
+        event.stopPropagation()
+      }
 
-        form.classList.add('was-validated')
-      }, false)
-    })
+      form.classList.add('was-validated')
+    }, false)
+  })
 })()