--- /dev/null
+/**
+ * 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);
+}
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