76 lines
1.9 KiB
JavaScript
76 lines
1.9 KiB
JavaScript
var now = require('performance-now')
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, root = typeof window === 'undefined' ? global : window
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, vendors = ['moz', 'webkit']
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, suffix = 'AnimationFrame'
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, raf = root['request' + suffix]
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, caf = root['cancel' + suffix] || root['cancelRequest' + suffix]
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for(var i = 0; !raf && i < vendors.length; i++) {
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raf = root[vendors[i] + 'Request' + suffix]
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caf = root[vendors[i] + 'Cancel' + suffix]
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|| root[vendors[i] + 'CancelRequest' + suffix]
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}
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// Some versions of FF have rAF but not cAF
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if(!raf || !caf) {
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var last = 0
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, id = 0
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, queue = []
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, frameDuration = 1000 / 60
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raf = function(callback) {
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if(queue.length === 0) {
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var _now = now()
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, next = Math.max(0, frameDuration - (_now - last))
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last = next + _now
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setTimeout(function() {
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var cp = queue.slice(0)
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// Clear queue here to prevent
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// callbacks from appending listeners
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// to the current frame's queue
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queue.length = 0
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for(var i = 0; i < cp.length; i++) {
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if(!cp[i].cancelled) {
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try{
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cp[i].callback(last)
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} catch(e) {
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setTimeout(function() { throw e }, 0)
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}
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}
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}
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}, Math.round(next))
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}
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queue.push({
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handle: ++id,
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callback: callback,
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cancelled: false
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})
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return id
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}
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caf = function(handle) {
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for(var i = 0; i < queue.length; i++) {
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if(queue[i].handle === handle) {
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queue[i].cancelled = true
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}
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}
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}
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}
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module.exports = function(fn) {
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// Wrap in a new function to prevent
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// `cancel` potentially being assigned
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// to the native rAF function
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return raf.call(root, fn)
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}
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module.exports.cancel = function() {
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caf.apply(root, arguments)
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}
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module.exports.polyfill = function(object) {
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if (!object) {
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object = root;
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}
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object.requestAnimationFrame = raf
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object.cancelAnimationFrame = caf
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}
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