Merge pull request #46 from vadimkorr/feature/45-promisify-functions

feature/45 Promisify functions

Author: vadimkorr

src/components/Carousel/Carousel.svelte

@@ -13,30 +13,19 @@
   } from '../../utils/event'
   import { getAdjacentIndexes } from '../../utils/page'
   import { get } from '../../utils/object'
-  import { ProgressManager } from '../../utils/ProgressManager.js'
+  import { ProgressManager } from '../../utils/ProgressManager'
+  import { wait } from '../../utils/interval'
 
   const dispatch = createEventDispatcher()
 
   const autoplayDirectionFnDescription = {
-    [NEXT]: () => {
-      progressManager.start(() => {
-        showNextPage()
-      })
-    },
-    [PREV]: () => {
-      progressManager.start(() => {
-        showPrevPage()
-      })
-    }
+    [NEXT]: async () => await progressManager.start(showNextPage),
+    [PREV]: async () => await progressManager.start(showPrevPage)
   }
 
   const directionFnDescription = {
-    [NEXT]: () => {
-      showNextPage()
-    },
-    [PREV]: () => {
-      showPrevPage()
-    }
+    [NEXT]: showNextPage,
+    [PREV]: showPrevPage
   }
 
   /**
@@ -70,6 +59,9 @@
    * Enables autoplay of pages
    */
   export let autoplay = false
+  $: {
+    applyAutoplayIfNeeded(autoplay)
+  }
 
   /**
    * Autoplay change interval (ms)
@@ -96,31 +88,42 @@
    */
   export let dots = true
 
-  export function goTo(pageIndex, options) {
+  export async function goTo(pageIndex, options) {
     const animated = get(options, 'animated', true)
     if (typeof pageIndex !== 'number') {
       throw new Error('pageIndex should be a number')
     }
-    showPage(pageIndex + Number(infinite), { animated })
+    await showPage(pageIndex + Number(infinite), { animated })
   }
 
-  export function goToPrev(options) {
+  export async function goToPrev(options) {
     const animated = get(options, 'animated', true)
-    showPrevPage({ animated })
+    await showPrevPage({ animated })
   }
 
-  export function goToNext(options) {
+  export async function goToNext(options) {
     const animated = get(options, 'animated', true)
-    showNextPage({ animated })
+    await showNextPage({ animated })
   }
 
   let store = createStore()
   let currentPageIndex = 0
-  $: originalCurrentPageIndex = currentPageIndex - Number(infinite);
+  $: originalCurrentPageIndex = getOriginalCurrentPageIndex(currentPageIndex, pagesCount, infinite) // index without cloenes
   $: dispatch('pageChange', originalCurrentPageIndex)
 
   let pagesCount = 0
   $: originalPagesCount = Math.max(pagesCount - (infinite ? 2 : 0), 1) // without clones
+
+  function getOriginalCurrentPageIndex(currentPageIndex, pagesCount, infinite) {
+    if (infinite) {
+      const CLONES_COUNT = 2
+      if (currentPageIndex === pagesCount - 1) return 0
+      if (currentPageIndex === 0) return (pagesCount - CLONES_COUNT) - 1
+      return currentPageIndex - 1
+    }
+    return currentPageIndex
+  }
+
   let pageWidth = 0
   let offset = 0
   let pageWindowElement
@@ -169,7 +172,7 @@
     pagesElement.append(first.cloneNode(true))
   }
 
-  function applyAutoplayIfNeeded(options) {
+  async function applyAutoplayIfNeeded(autoplay) {
     // prevent progress change if not infinite for first and last page
     if (
       !infinite && (
@@ -180,16 +183,8 @@
       progressManager.reset()
       return
     }
-    if (autoplay) {
-      const delayMs = get(options, 'delayMs', 0)
-      if (delayMs) {
-        setTimeout(() => {
-          autoplayDirectionFnDescription[autoplayDirection]()
-        }, delayMs)
-      } else {
-        autoplayDirectionFnDescription[autoplayDirection]()
-      }
-    }
+
+    autoplay && await autoplayDirectionFnDescription[autoplayDirection]()
   }
 
   let cleanupFns = []
@@ -211,8 +206,6 @@
         applyPageSizes()
       }
 
-      applyAutoplayIfNeeded()
-
       addResizeEventListener(applyPageSizes)
     })()
   })
@@ -222,26 +215,30 @@
     cleanupFns.filter(fn => fn && typeof fn === 'function').forEach(fn => fn())
   })
 
-  function handlePageChange(pageIndex) {
-    showPage(pageIndex + Number(infinite))
+  async function handlePageChange(pageIndex) {
+    await showPage(pageIndex + Number(infinite))
   }
 
   function offsetPage(animated) {
-    // _duration is an offset animation time
-    _duration = animated ? duration : 0
-    offset = -currentPageIndex * pageWidth
+    return new Promise((resolve) => {
+      // _duration is an offset animation time
+      _duration = animated ? duration : 0
+      offset = -currentPageIndex * pageWidth
+      setTimeout(() => {
+        resolve()
+      }, _duration)
+    })
   }
 
   // makes delayed jump to 1st or last element
-  function jumpIfNeeded() {
+  async function jumpIfNeeded() {
     let jumped = false
     if (infinite) {
       if (currentPageIndex === 0) {
-        // offsetDelayMs should depend on _duration, as it wait when offset finishes
-        showPage(pagesCount - 2, { offsetDelayMs: _duration, animated: false })
+        await showPage(pagesCount - 2, { animated: false })
         jumped = true
       } else if (currentPageIndex === pagesCount - 1) {
-        showPage(1, { offsetDelayMs: _duration, animated: false })
+        await showPage(1, { animated: false })
         jumped = true
       }
     }
@@ -250,54 +247,43 @@
 
   // Disable page change while animation is in progress
   let disabled = false
-  function safeChangePage(cb, options) {
-    const animated = get(options, 'animated', true)
+  async function changePage(updateStoreFn, options) {
     if (disabled) return
-    cb()
     disabled = true
-    setTimeout(() => {
-      disabled = false
-    }, animated ? duration : 0)
+
+    updateStoreFn()
+    await offsetPage(get(options, 'animated', true))
+    disabled = false
+
+    const jumped = await jumpIfNeeded()
+    !jumped && applyAutoplayIfNeeded(autoplay) // no need to wait it finishes
   }
 
-  function showPage(pageIndex, options) {
-    const animated = get(options, 'animated', true)
-    const offsetDelayMs = get(options, 'offsetDelayMs', 0)
-    safeChangePage(() => {
-      store.moveToPage({ pageIndex, pagesCount })
-      // delayed page transition, used for infinite autoplay to jump to real page
-      setTimeout(() => {
-        offsetPage(animated)
-        const jumped = jumpIfNeeded()
-        !jumped && applyAutoplayIfNeeded({ delayMs: _duration }) // while offset animation is in progress (delayMs = _duration ms) wait for it
-      }, offsetDelayMs)
-    }, { animated })
+  async function showPage(pageIndex, options) {
+    await changePage(
+      () => store.moveToPage({ pageIndex, pagesCount }),
+      options
+    )
   }
-  function showPrevPage(options) {
-    const animated = get(options, 'animated', true)
-    safeChangePage(() => {
-      store.prev({ infinite, pagesCount })
-      offsetPage(animated)
-      const jumped = jumpIfNeeded()
-      !jumped && applyAutoplayIfNeeded({ delayMs: _duration })
-    }, { animated })
+  async function showPrevPage(options) {
+    await changePage(
+      () => store.prev({ infinite, pagesCount }),
+      options
+    )
   }
-  function showNextPage(options) {
-    const animated = get(options, 'animated', true)
-    safeChangePage(() => {
-      store.next({ infinite, pagesCount })
-      offsetPage(animated)
-      const jumped = jumpIfNeeded()
-      !jumped && applyAutoplayIfNeeded({ delayMs: _duration })
-    }, { animated })
+  async function showNextPage(options) {
+    await changePage(
+      () => store.next({ infinite, pagesCount }),
+      options
+    )
   }
 
   // gestures
   function handleSwipeStart() {
     _duration = 0
   }
-  function handleThreshold(event) {
-    directionFnDescription[event.detail.direction]()
+  async function handleThreshold(event) {
+    await directionFnDescription[event.detail.direction]()
   }
   function handleSwipeMove(event) {
     offset += event.detail.dx

src/utils/ProgressManager.js

@@ -1,6 +1,8 @@
 import { setIntervalImmediate } from './interval'
 
 const STEP_MS = 35
+const MAX_VALUE = 1
+
 export class ProgressManager {
   #autoplayDuration
   #onProgressValueChange
@@ -17,25 +19,28 @@ export class ProgressManager {
   }
 
   start(onFinish) {
-    this.reset()
-
-    const stepMs = Math.min(STEP_MS, this.#autoplayDuration)
-    let progress = -stepMs
-
-    this.#interval = setIntervalImmediate(() => {
-      if (this.#paused) {
-        return 
-      }
-      progress += stepMs
-
-      const value = progress / this.#autoplayDuration
-      this.#onProgressValueChange(value)
-
-      if (value > 1) {
-        this.reset()
-        onFinish()
-      }
-    }, stepMs)
+    return new Promise((resolve) => {
+      this.reset()
+
+      const stepMs = Math.min(STEP_MS, this.#autoplayDuration)
+      let progress = -stepMs
+  
+      this.#interval = setIntervalImmediate(async () => {
+        if (this.#paused) {
+          return
+        }
+        progress += stepMs
+  
+        const value = progress / this.#autoplayDuration
+        this.#onProgressValueChange(value)
+  
+        if (value > MAX_VALUE) {
+          this.reset()
+          await onFinish()
+          resolve()
+        }
+      }, stepMs)
+    })
   }
 
   pause() {
@@ -48,5 +53,6 @@ export class ProgressManager {
 
   reset() {
     clearInterval(this.#interval)
+    this.#onProgressValueChange(MAX_VALUE)
   }
 }

src/utils/interval.js

@@ -2,3 +2,11 @@ export const setIntervalImmediate = (fn, ms) => {
   fn();
   return setInterval(fn, ms);
 }
+
+export const wait = (ms) => {
+  return new Promise((resolve) => {
+    setTimeout(() => {
+      resolve()
+    }, ms)
+  })
+}

src/utils/interval.test.js

@@ -1,5 +1,6 @@
 import {
   setIntervalImmediate,
+  wait
 } from './interval.js'
 
 describe('setIntervalImmediate', () => {
@@ -28,3 +29,18 @@ describe('setIntervalImmediate', () => {
     expect(clearInterval).toHaveBeenCalledWith(interval)
   })
 })
+
+describe('wait', () => {
+  beforeEach(() => {
+    jest.useFakeTimers();
+  })
+
+  it('wait n ms', () => {
+    const ms = 1000
+
+    wait(ms)
+    jest.runAllTimers()
+
+    expect(setTimeout).toHaveBeenCalledWith(expect.any(Function), ms)
+  })
+})