Switch to strings constants.

This allows the minifier to mangle the constants. It also allows the linter to find unused strings properly.

While at it, remove a few unused properties.

File                        Before      After       Diff
--------------------------------------------------------
bootstrap.bundle.min.js     23.61 kB    22.61 kB    -1.00 kB (-4.23 %)
bootstrap.min.js            17.04 kB    16.08 kB    -0.96 kB (-5.63 %)

1 files changed, 45 insertions, 53 deletions

diff --git a/js/src/collapse.js b/js/src/collapse.js
index 27eef4ef72..3b78c5cdb3 100644
--- a/js/src/collapse.js
+++ b/js/src/collapse.js
@@ -44,30 +44,22 @@ const DefaultType = {
   parent: '(string|element)'
 }
 
-const Event = {
-  SHOW: `show${EVENT_KEY}`,
-  SHOWN: `shown${EVENT_KEY}`,
-  HIDE: `hide${EVENT_KEY}`,
-  HIDDEN: `hidden${EVENT_KEY}`,
-  CLICK_DATA_API: `click${EVENT_KEY}${DATA_API_KEY}`
-}
+const EVENT_SHOW = `show${EVENT_KEY}`
+const EVENT_SHOWN = `shown${EVENT_KEY}`
+const EVENT_HIDE = `hide${EVENT_KEY}`
+const EVENT_HIDDEN = `hidden${EVENT_KEY}`
+const EVENT_CLICK_DATA_API = `click${EVENT_KEY}${DATA_API_KEY}`
 
-const ClassName = {
-  SHOW: 'show',
-  COLLAPSE: 'collapse',
-  COLLAPSING: 'collapsing',
-  COLLAPSED: 'collapsed'
-}
+const CLASS_NAME_SHOW = 'show'
+const CLASS_NAME_COLLAPSE = 'collapse'
+const CLASS_NAME_COLLAPSING = 'collapsing'
+const CLASS_NAME_COLLAPSED = 'collapsed'
 
-const Dimension = {
-  WIDTH: 'width',
-  HEIGHT: 'height'
-}
+const WIDTH = 'width'
+const HEIGHT = 'height'
 
-const Selector = {
-  ACTIVES: '.show, .collapsing',
-  DATA_TOGGLE: '[data-toggle="collapse"]'
-}
+const SELECTOR_ACTIVES = '.show, .collapsing'
+const SELECTOR_DATA_TOGGLE = '[data-toggle="collapse"]'
 
 /**
  * ------------------------------------------------------------------------
@@ -81,11 +73,11 @@ class Collapse {
     this._element = element
     this._config = this._getConfig(config)
     this._triggerArray = makeArray(SelectorEngine.find(
-      `${Selector.DATA_TOGGLE}[href="#${element.id}"],` +
-      `${Selector.DATA_TOGGLE}[data-target="#${element.id}"]`
+      `${SELECTOR_DATA_TOGGLE}[href="#${element.id}"],` +
+      `${SELECTOR_DATA_TOGGLE}[data-target="#${element.id}"]`
     ))
 
-    const toggleList = makeArray(SelectorEngine.find(Selector.DATA_TOGGLE))
+    const toggleList = makeArray(SelectorEngine.find(SELECTOR_DATA_TOGGLE))
     for (let i = 0, len = toggleList.length; i < len; i++) {
       const elem = toggleList[i]
       const selector = getSelectorFromElement(elem)
@@ -124,7 +116,7 @@ class Collapse {
   // Public
 
   toggle() {
-    if (this._element.classList.contains(ClassName.SHOW)) {
+    if (this._element.classList.contains(CLASS_NAME_SHOW)) {
       this.hide()
     } else {
       this.show()
@@ -133,7 +125,7 @@ class Collapse {
 
   show() {
     if (this._isTransitioning ||
-      this._element.classList.contains(ClassName.SHOW)) {
+      this._element.classList.contains(CLASS_NAME_SHOW)) {
       return
     }
 
@@ -141,13 +133,13 @@ class Collapse {
     let activesData
 
     if (this._parent) {
-      actives = makeArray(SelectorEngine.find(Selector.ACTIVES, this._parent))
+      actives = makeArray(SelectorEngine.find(SELECTOR_ACTIVES, this._parent))
         .filter(elem => {
           if (typeof this._config.parent === 'string') {
             return elem.getAttribute('data-parent') === this._config.parent
           }
 
-          return elem.classList.contains(ClassName.COLLAPSE)
+          return elem.classList.contains(CLASS_NAME_COLLAPSE)
         })
 
       if (actives.length === 0) {
@@ -165,7 +157,7 @@ class Collapse {
       }
     }
 
-    const startEvent = EventHandler.trigger(this._element, Event.SHOW)
+    const startEvent = EventHandler.trigger(this._element, EVENT_SHOW)
     if (startEvent.defaultPrevented) {
       return
     }
@@ -184,14 +176,14 @@ class Collapse {
 
     const dimension = this._getDimension()
 
-    this._element.classList.remove(ClassName.COLLAPSE)
-    this._element.classList.add(ClassName.COLLAPSING)
+    this._element.classList.remove(CLASS_NAME_COLLAPSE)
+    this._element.classList.add(CLASS_NAME_COLLAPSING)
 
     this._element.style[dimension] = 0
 
     if (this._triggerArray.length) {
       this._triggerArray.forEach(element => {
-        element.classList.remove(ClassName.COLLAPSED)
+        element.classList.remove(CLASS_NAME_COLLAPSED)
         element.setAttribute('aria-expanded', true)
       })
     }
@@ -199,15 +191,15 @@ class Collapse {
     this.setTransitioning(true)
 
     const complete = () => {
-      this._element.classList.remove(ClassName.COLLAPSING)
-      this._element.classList.add(ClassName.COLLAPSE)
-      this._element.classList.add(ClassName.SHOW)
+      this._element.classList.remove(CLASS_NAME_COLLAPSING)
+      this._element.classList.add(CLASS_NAME_COLLAPSE)
+      this._element.classList.add(CLASS_NAME_SHOW)
 
       this._element.style[dimension] = ''
 
       this.setTransitioning(false)
 
-      EventHandler.trigger(this._element, Event.SHOWN)
+      EventHandler.trigger(this._element, EVENT_SHOWN)
     }
 
     const capitalizedDimension = dimension[0].toUpperCase() + dimension.slice(1)
@@ -222,11 +214,11 @@ class Collapse {
 
   hide() {
     if (this._isTransitioning ||
-      !this._element.classList.contains(ClassName.SHOW)) {
+      !this._element.classList.contains(CLASS_NAME_SHOW)) {
       return
     }
 
-    const startEvent = EventHandler.trigger(this._element, Event.HIDE)
+    const startEvent = EventHandler.trigger(this._element, EVENT_HIDE)
     if (startEvent.defaultPrevented) {
       return
     }
@@ -237,9 +229,9 @@ class Collapse {
 
     reflow(this._element)
 
-    this._element.classList.add(ClassName.COLLAPSING)
-    this._element.classList.remove(ClassName.COLLAPSE)
-    this._element.classList.remove(ClassName.SHOW)
+    this._element.classList.add(CLASS_NAME_COLLAPSING)
+    this._element.classList.remove(CLASS_NAME_COLLAPSE)
+    this._element.classList.remove(CLASS_NAME_SHOW)
 
     const triggerArrayLength = this._triggerArray.length
     if (triggerArrayLength > 0) {
@@ -247,8 +239,8 @@ class Collapse {
         const trigger = this._triggerArray[i]
         const elem = getElementFromSelector(trigger)
 
-        if (elem && !elem.classList.contains(ClassName.SHOW)) {
-          trigger.classList.add(ClassName.COLLAPSED)
+        if (elem && !elem.classList.contains(CLASS_NAME_SHOW)) {
+          trigger.classList.add(CLASS_NAME_COLLAPSED)
           trigger.setAttribute('aria-expanded', false)
         }
       }
@@ -258,9 +250,9 @@ class Collapse {
 
     const complete = () => {
       this.setTransitioning(false)
-      this._element.classList.remove(ClassName.COLLAPSING)
-      this._element.classList.add(ClassName.COLLAPSE)
-      EventHandler.trigger(this._element, Event.HIDDEN)
+      this._element.classList.remove(CLASS_NAME_COLLAPSING)
+      this._element.classList.add(CLASS_NAME_COLLAPSE)
+      EventHandler.trigger(this._element, EVENT_HIDDEN)
     }
 
     this._element.style[dimension] = ''
@@ -297,8 +289,8 @@ class Collapse {
   }
 
   _getDimension() {
-    const hasWidth = this._element.classList.contains(Dimension.WIDTH)
-    return hasWidth ? Dimension.WIDTH : Dimension.HEIGHT
+    const hasWidth = this._element.classList.contains(WIDTH)
+    return hasWidth ? WIDTH : HEIGHT
   }
 
   _getParent() {
@@ -313,7 +305,7 @@ class Collapse {
       parent = SelectorEngine.findOne(parent)
     }
 
-    const selector = `${Selector.DATA_TOGGLE}[data-parent="${parent}"]`
+    const selector = `${SELECTOR_DATA_TOGGLE}[data-parent="${parent}"]`
 
     makeArray(SelectorEngine.find(selector, parent))
       .forEach(element => {
@@ -330,14 +322,14 @@ class Collapse {
 
   _addAriaAndCollapsedClass(element, triggerArray) {
     if (element) {
-      const isOpen = element.classList.contains(ClassName.SHOW)
+      const isOpen = element.classList.contains(CLASS_NAME_SHOW)
 
       if (triggerArray.length) {
         triggerArray.forEach(elem => {
           if (isOpen) {
-            elem.classList.remove(ClassName.COLLAPSED)
+            elem.classList.remove(CLASS_NAME_COLLAPSED)
           } else {
-            elem.classList.add(ClassName.COLLAPSED)
+            elem.classList.add(CLASS_NAME_COLLAPSED)
           }
 
           elem.setAttribute('aria-expanded', isOpen)
@@ -390,7 +382,7 @@ class Collapse {
  * ------------------------------------------------------------------------
  */
 
-EventHandler.on(document, Event.CLICK_DATA_API, Selector.DATA_TOGGLE, function (event) {
+EventHandler.on(document, EVENT_CLICK_DATA_API, SELECTOR_DATA_TOGGLE, function (event) {
   // preventDefault only for <a> elements (which change the URL) not inside the collapsible element
   if (event.target.tagName === 'A') {
     event.preventDefault()