refactor: move to const variables and simplify conditionals (#666)

src/components/build.js

@@ -32,8 +32,8 @@ export default function (Glide, Components, Events) {
      * @return {Void}
      */
     activeClass () {
-      let classes = Glide.settings.classes
-      let slide = Components.Html.slides[Glide.index]
+      const classes = Glide.settings.classes
+      const slide = Components.Html.slides[Glide.index]
 
       if (slide) {
         slide.classList.add(classes.slide.active)

src/components/clones.js

@@ -19,26 +19,26 @@ export default function (Glide, Components, Events) {
      * @return {[]}
      */
     collect (items = []) {
-      let { slides } = Components.Html
-      let { perView, classes, cloningRatio } = Glide.settings
+      const { slides } = Components.Html
+      const { perView, classes, cloningRatio } = Glide.settings
 
-      if (slides.length !== 0) {
+      if (slides.length > 0) {
         const peekIncrementer = +!!Glide.settings.peek
         const cloneCount = perView + peekIncrementer + Math.round(perView / 2)
         const append = slides.slice(0, cloneCount).reverse()
         const prepend = slides.slice(cloneCount * -1)
 
         for (let r = 0; r < Math.max(cloningRatio, Math.floor(perView / slides.length)); r++) {
           for (let i = 0; i < append.length; i++) {
-            let clone = append[i].cloneNode(true)
+            const clone = append[i].cloneNode(true)
 
             clone.classList.add(classes.slide.clone)
 
             items.push(clone)
           }
 
           for (let i = 0; i < prepend.length; i++) {
-            let clone = prepend[i].cloneNode(true)
+            const clone = prepend[i].cloneNode(true)
 
             clone.classList.add(classes.slide.clone)
 
@@ -56,8 +56,8 @@ export default function (Glide, Components, Events) {
      * @return {Void}
      */
     append () {
-      let { items } = this
-      let { wrapper, slides } = Components.Html
+      const { items } = this
+      const { wrapper, slides } = Components.Html
 
       const half = Math.floor(items.length / 2)
       const prepend = items.slice(0, half).reverse()

src/components/controls.js

@@ -17,7 +17,7 @@ export default function (Glide, Components, Events) {
    */
   const Binder = new EventsBinder()
 
-  let capture = (supportsPassive) ? { passive: true } : false
+  const capture = (supportsPassive) ? { passive: true } : false
 
   const Controls = {
     /**
@@ -93,13 +93,11 @@ export default function (Glide, Components, Events) {
         return
       }
 
-      if (item) {
-        item.classList.add(settings.classes.nav.active)
+      item.classList.add(settings.classes.nav.active)
 
-        siblings(item).forEach(sibling => {
-          sibling.classList.remove(settings.classes.nav.active)
-        })
-      }
+      siblings(item).forEach(sibling => {
+        sibling.classList.remove(settings.classes.nav.active)
+      })
     },
 
     /**
@@ -109,11 +107,9 @@ export default function (Glide, Components, Events) {
      * @return {Void}
      */
     removeClass (controls) {
-      let item = controls[Glide.index]
+      const item = controls[Glide.index]
 
-      if (item) {
-        item.classList.remove(Glide.settings.classes.nav.active)
-      }
+      item?.classList.remove(Glide.settings.classes.nav.active)
     },
 
     /**

src/components/direction.js

@@ -26,7 +26,7 @@ export default function (Glide, Components, Events) {
      * @returns {String}
      */
     resolve (pattern) {
-      let token = pattern.slice(0, 1)
+      const token = pattern.slice(0, 1)
 
       if (this.is('rtl')) {
         return pattern.split(token).join(FLIPED_MOVEMENTS[token])

src/components/gaps.js

@@ -18,8 +18,8 @@ export default function (Glide, Components, Events) {
      */
     apply (slides) {
       for (let i = 0, len = slides.length; i < len; i++) {
-        let style = slides[i].style
-        let direction = Components.Direction.value
+        const style = slides[i].style
+        const direction = Components.Direction.value
 
         if (i !== 0) {
           style[MARGIN_TYPE[direction][0]] = `${this.value / 2}px`
@@ -43,7 +43,7 @@ export default function (Glide, Components, Events) {
     */
     remove (slides) {
       for (let i = 0, len = slides.length; i < len; i++) {
-        let style = slides[i].style
+        const style = slides[i].style
 
         style.marginLeft = ''
         style.marginRight = ''
@@ -82,7 +82,7 @@ export default function (Glide, Components, Events) {
      * @returns {Number}
      */
     get () {
-      let perView = Glide.settings.perView
+      const perView = Glide.settings.perView
 
       return (Gaps.value * (perView - 1)) / perView
     }

src/components/keyboard.js

@@ -47,12 +47,9 @@ export default function (Glide, Components, Events) {
     press (event) {
       const { perSwipe } = Glide.settings
 
-      if (event.code === 'ArrowRight') {
-        Components.Run.make(Components.Direction.resolve(`${perSwipe}>`))
-      }
-
-      if (event.code === 'ArrowLeft') {
-        Components.Run.make(Components.Direction.resolve(`${perSwipe}<`))
+      const arrowSymbols = { ArrowRight: '>', ArrowLeft: '<' }
+      if (['ArrowRight', 'ArrowLeft'].includes(event.code)) {
+        Components.Run.make(Components.Direction.resolve(`${perSwipe}${arrowSymbols[event.code]}`))
       }
     }
   }

src/components/move.js

@@ -71,8 +71,8 @@ export default function (Glide, Components, Events) {
      * @return {Number}
      */
     get () {
-      let offset = this.offset
-      let translate = this.translate
+      const offset = this.offset
+      const translate = this.translate
 
       if (Components.Direction.is('rtl')) {
         return translate + offset

src/components/peek.js

@@ -48,8 +48,8 @@ export default function (Glide, Components, Events) {
      * @returns {Number}
      */
     get () {
-      let value = Peek.value
-      let perView = Glide.settings.perView
+      const value = Peek.value
+      const perView = Glide.settings.perView
 
       if (isObject(value)) {
         return (value.before / perView) + (value.after / perView)

src/components/sizes.js

@@ -8,8 +8,8 @@ export default function (Glide, Components, Events) {
      * @return {Void}
      */
     setupSlides () {
-      let width = `${this.slideWidth}px`
-      let slides = Components.Html.slides
+      const width = `${this.slideWidth}px`
+      const slides = Components.Html.slides
 
       for (let i = 0; i < slides.length; i++) {
         slides[i].style.width = width
@@ -31,7 +31,7 @@ export default function (Glide, Components, Events) {
      * @returns {Void}
      */
     remove () {
-      let slides = Components.Html.slides
+      const slides = Components.Html.slides
 
       for (let i = 0; i < slides.length; i++) {
         slides[i].style.width = ''

src/components/swipe.js

@@ -21,7 +21,7 @@ export default function (Glide, Components, Events) {
   let swipeStartX = 0
   let swipeStartY = 0
   let disabled = false
-  let capture = (supportsPassive) ? { passive: true } : false
+  const capture = (supportsPassive) ? { passive: true } : false
 
   const Swipe = {
     /**
@@ -43,7 +43,7 @@ export default function (Glide, Components, Events) {
       if (!disabled && !Glide.disabled) {
         this.disable()
 
-        let swipe = this.touches(event)
+        const swipe = this.touches(event)
 
         swipeSin = null
         swipeStartX = toInt(swipe.pageX)
@@ -65,14 +65,14 @@ export default function (Glide, Components, Events) {
       if (!Glide.disabled) {
         const { touchAngle, touchRatio, classes } = Glide.settings
 
-        let swipe = this.touches(event)
+        const swipe = this.touches(event)
 
-        let subExSx = toInt(swipe.pageX) - swipeStartX
-        let subEySy = toInt(swipe.pageY) - swipeStartY
-        let powEX = Math.abs(subExSx << 2)
-        let powEY = Math.abs(subEySy << 2)
-        let swipeHypotenuse = Math.sqrt(powEX + powEY)
-        let swipeCathetus = Math.sqrt(powEY)
+        const subExSx = toInt(swipe.pageX) - swipeStartX
+        const subEySy = toInt(swipe.pageY) - swipeStartY
+        const powEX = Math.abs(subExSx << 2)
+        const powEY = Math.abs(subEySy << 2)
+        const swipeHypotenuse = Math.sqrt(powEX + powEY)
+        const swipeCathetus = Math.sqrt(powEY)
 
         swipeSin = Math.asin(swipeCathetus / swipeHypotenuse)
 
@@ -100,11 +100,11 @@ export default function (Glide, Components, Events) {
       if (!Glide.disabled) {
         const { perSwipe, touchAngle, classes } = Glide.settings
 
-        let swipe = this.touches(event)
-        let threshold = this.threshold(event)
+        const swipe = this.touches(event)
+        const threshold = this.threshold(event)
 
-        let swipeDistance = swipe.pageX - swipeStartX
-        let swipeDeg = swipeSin * 180 / Math.PI
+        const swipeDistance = swipe.pageX - swipeStartX
+        const swipeDeg = swipeSin * 180 / Math.PI
 
         this.enable()
 
@@ -216,7 +216,7 @@ export default function (Glide, Components, Events) {
      * @return {Number}
      */
     threshold (event) {
-      let settings = Glide.settings
+      const settings = Glide.settings
 
       if (MOUSE_EVENTS.indexOf(event.type) > -1) {
         return settings.dragThreshold

src/components/transition.js

@@ -17,13 +17,13 @@ export default function (Glide, Components, Events) {
      * @return {String}
      */
     compose (property) {
-      let settings = Glide.settings
+      const settings = Glide.settings
 
-      if (!disabled) {
-        return `${property} ${this.duration}ms ${settings.animationTimingFunc}`
+      if (disabled) {
+        return `${property} 0ms ${settings.animationTimingFunc}`
       }
 
-      return `${property} 0ms ${settings.animationTimingFunc}`
+      return `${property} ${this.duration}ms ${settings.animationTimingFunc}`
     },
 
     /**
@@ -88,7 +88,7 @@ export default function (Glide, Components, Events) {
      * @return {Number}
      */
     get () {
-      let settings = Glide.settings
+      const settings = Glide.settings
 
       if (Glide.isType('slider') && Components.Run.offset) {
         return settings.rewindDuration

src/components/translate.js

@@ -9,7 +9,7 @@ export default function (Glide, Components, Events) {
      * @return {Void}
      */
     set (value) {
-      let transform = mutator(Glide, Components).mutate(value)
+      const transform = mutator(Glide, Components).mutate(value)
       const translate3d = `translate3d(${-1 * transform}px, 0px, 0px)`
 
       Components.Html.wrapper.style.mozTransform = translate3d // needed for supported Firefox 10-15

src/core/event/events-bus.js

@@ -32,7 +32,7 @@ export default class EventsBus {
     }
 
     // Add the handler to queue
-    var index = this.events[event].push(handler) - 1
+    const index = this.events[event].push(handler) - 1
 
     // Provide handle back for removal of event
     return {

src/mutator/transformers/focusing.js

@@ -14,10 +14,10 @@ export default function (Glide, Components) {
      * @return {Number}
      */
     modify (translate) {
-      let gap = Components.Gaps.value
-      let width = Components.Sizes.width
-      let focusAt = Glide.settings.focusAt
-      let slideWidth = Components.Sizes.slideWidth
+      const gap = Components.Gaps.value
+      const width = Components.Sizes.width
+      const focusAt = Glide.settings.focusAt
+      const slideWidth = Components.Sizes.slideWidth
 
       if (focusAt === 'center') {
         return translate - (width / 2 - slideWidth / 2)

src/mutator/transformers/peeking.js

@@ -17,7 +17,7 @@ export default function (Glide, Components) {
      */
     modify (translate) {
       if (Glide.settings.focusAt >= 0) {
-        let peek = Components.Peek.value
+        const peek = Components.Peek.value
 
         if (isObject(peek)) {
           return translate - peek.before

src/utils/dom.js

@@ -7,7 +7,7 @@
 export function siblings (node) {
   if (node && node.parentNode) {
     let n = node.parentNode.firstChild
-    let matched = []
+    const matched = []
 
     for (; n; n = n.nextSibling) {
       if (n.nodeType === 1 && n !== node) {

src/utils/object.js

@@ -42,25 +42,12 @@ export function mergeOptions (defaults, settings) {
   if (settings.hasOwnProperty('classes')) {
     options.classes = Object.assign({}, defaults.classes, settings.classes)
 
-    if (settings.classes.hasOwnProperty('direction')) {
-      options.classes.direction = Object.assign({}, defaults.classes.direction, settings.classes.direction)
-    }
-
-    if (settings.classes.hasOwnProperty('type')) {
-      options.classes.type = Object.assign({}, defaults.classes.type, settings.classes.type)
-    }
-
-    if (settings.classes.hasOwnProperty('slide')) {
-      options.classes.slide = Object.assign({}, defaults.classes.slide, settings.classes.slide)
-    }
-
-    if (settings.classes.hasOwnProperty('arrow')) {
-      options.classes.arrow = Object.assign({}, defaults.classes.arrow, settings.classes.arrow)
-    }
-
-    if (settings.classes.hasOwnProperty('nav')) {
-      options.classes.nav = Object.assign({}, defaults.classes.nav, settings.classes.nav)
-    }
+    const properties = ['direction', 'type', 'slide', 'arrow', 'nav']
+    properties.forEach(property => {
+      if (settings.classes.hasOwnProperty(property)) {
+        options.classes[property] = { ...defaults.classes[property], ...settings.classes[property] }
+      }
+    })
   }
 
   if (settings.hasOwnProperty('breakpoints')) {

src/utils/wait.js

@@ -11,19 +11,18 @@ import { now } from './time'
  *
  * @see https://github.com/jashkenas/underscore
  */
-export function throttle (func, wait, options) {
+export function throttle (func, wait, options = {}) {
   let timeout, context, args, result
   let previous = 0
-  if (!options) options = {}
 
-  let later = function () {
+  const later = function () {
     previous = options.leading === false ? 0 : now()
     timeout = null
     result = func.apply(context, args)
     if (!timeout) context = args = null
   }
 
-  let throttled = function () {
+  const throttled = function () {
     let at = now()
     if (!previous && options.leading === false) previous = at
     let remaining = wait - (at - previous)