From 2b929f5d951e7a31ec3176607b9bcdbeeeb785f1 Mon Sep 17 00:00:00 2001
From: Dan Brown <ssddanbrown@googlemail.com>
Date: Fri, 7 Jun 2019 15:51:01 +0100
Subject: [PATCH] Added custom slideUp/slideDown animations using plain JS

---
 resources/assets/js/components/collapsible.js |  6 +-
 resources/assets/js/services/animations.js    | 91 +++++++++++++++++++
 2 files changed, 95 insertions(+), 2 deletions(-)
 create mode 100644 resources/assets/js/services/animations.js

diff --git a/resources/assets/js/components/collapsible.js b/resources/assets/js/components/collapsible.js
index a13b367d3..40ab32508 100644
--- a/resources/assets/js/components/collapsible.js
+++ b/resources/assets/js/components/collapsible.js
@@ -1,3 +1,5 @@
+import {slideDown, slideUp} from "../services/animations";
+
 /**
  * Collapsible
  * Provides some simple logic to allow collapsible sections.
@@ -16,12 +18,12 @@ class Collapsible {
 
     open() {
         this.elem.classList.add('open');
-        $(this.content).slideDown(400);
+        slideDown(this.content, 300);
     }
 
     close() {
         this.elem.classList.remove('open');
-        $(this.content).slideUp(400);
+        slideUp(this.content, 300);
     }
 
     toggle() {
diff --git a/resources/assets/js/services/animations.js b/resources/assets/js/services/animations.js
new file mode 100644
index 000000000..5cb90b70c
--- /dev/null
+++ b/resources/assets/js/services/animations.js
@@ -0,0 +1,91 @@
+/**
+ * Hide the element by sliding the contents upwards.
+ * @param {Element} element
+ * @param {Number} animTime
+ */
+export function slideUp(element, animTime = 400) {
+    const currentHeight = element.getBoundingClientRect().height;
+    const computedStyles = getComputedStyle(element);
+    const currentPaddingTop = computedStyles.getPropertyValue('padding-top');
+    const currentPaddingBottom = computedStyles.getPropertyValue('padding-bottom');
+    const animStyles = {
+        height: [`${currentHeight}px`, '0px'],
+        overflow: ['hidden', 'hidden'],
+        paddingTop: [currentPaddingTop, '0px'],
+        paddingBottom: [currentPaddingBottom, '0px'],
+    };
+
+    animateStyles(element, animStyles, animTime, () => {
+        element.style.display = 'none';
+    });
+}
+
+/**
+ * Show the given element by expanding the contents.
+ * @param {Element} element - Element to animate
+ * @param {Number} animTime - Animation time in ms
+ */
+export function slideDown(element, animTime = 400) {
+    element.style.display = 'block';
+    const targetHeight = element.getBoundingClientRect().height;
+    const computedStyles = getComputedStyle(element);
+    const targetPaddingTop = computedStyles.getPropertyValue('padding-top');
+    const targetPaddingBottom = computedStyles.getPropertyValue('padding-bottom');
+    const animStyles = {
+        height: ['0px', `${targetHeight}px`],
+        overflow: ['hidden', 'hidden'],
+        paddingTop: ['0px', targetPaddingTop],
+        paddingBottom: ['0px', targetPaddingBottom],
+    };
+
+    animateStyles(element, animStyles, animTime);
+}
+
+/**
+ * Used in the function below to store references of clean-up functions.
+ * Used to ensure only one transitionend function exists at any time.
+ * @type {WeakMap<object, any>}
+ */
+const animateStylesCleanupMap = new WeakMap();
+
+/**
+ * Animate the css styles of an element using FLIP animation techniques.
+ * Styles must be an object where the keys are style properties, camelcase, and the values
+ * are an array of two items in the format [initialValue, finalValue]
+ * @param {Element} element
+ * @param {Object} styles
+ * @param {Number} animTime
+ * @param {Function} onComplete
+ */
+function animateStyles(element, styles, animTime = 400, onComplete = null) {
+    const styleNames = Object.keys(styles);
+    for (let style of styleNames) {
+        element.style[style] = styles[style][0];
+    }
+
+    const cleanup = () => {
+        for (let style of styleNames) {
+            element.style[style] = null;
+        }
+        element.style.transition = null;
+        element.removeEventListener('transitionend', cleanup);
+        if (onComplete) onComplete();
+    };
+
+    setTimeout(() => {
+        requestAnimationFrame(() => {
+            element.style.transition = `all ease-in-out ${animTime}ms`;
+            for (let style of styleNames) {
+                element.style[style] = styles[style][1];
+            }
+
+            if (animateStylesCleanupMap.has(element)) {
+                const oldCleanup = animateStylesCleanupMap.get(element);
+                element.removeEventListener('transitionend', oldCleanup);
+            }
+
+            element.addEventListener('transitionend', cleanup);
+            animateStylesCleanupMap.set(element, cleanup);
+        });
+    }, 10);
+}
\ No newline at end of file