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Merge pull request #410 from griffpatch/optimisation/only-check-for-compatability-once
Optimisation - Only check browser compatability once
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commit
4bb5f30bd8
1 changed files with 27 additions and 17 deletions
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@ -23,16 +23,35 @@ var Timer = function () {};
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*/
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Timer.prototype.startTime = 0;
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/**
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* Disable use of self.performance for now as it results in lower performance
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* However, instancing it like below (caching the self.performance to a local variable) negates most of the issues.
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* @type {boolean}
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*/
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var USE_PERFORMANCE = false;
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/**
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* Legacy object to allow for us to call now to get the old style date time (for backwards compatibility)
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* @deprecated This is only called via the nowObj.now() if no other means is possible...
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*/
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var legacyDateCode = {
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now: function () {
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return new Date().getTime();
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}
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};
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/**
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* Use this object to route all time functions through single access points.
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*/
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var nowObj = (USE_PERFORMANCE && typeof self !== 'undefined' && self.performance && 'now' in self.performance) ?
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self.performance : Date.now ? Date : legacyDateCode;
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/**
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* Return the currently known absolute time, in ms precision.
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* @returns {number} ms elapsed since 1 January 1970 00:00:00 UTC.
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*/
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Timer.prototype.time = function () {
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if (Date.now) {
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return Date.now();
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} else {
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return new Date().getTime();
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}
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return nowObj.now();
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};
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/**
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@ -43,12 +62,7 @@ Timer.prototype.time = function () {
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* @returns {number} ms-scale accurate time relative to other relative times.
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*/
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Timer.prototype.relativeTime = function () {
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if (typeof self !== 'undefined' &&
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self.performance && 'now' in self.performance) {
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return self.performance.now();
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} else {
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return this.time();
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}
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return nowObj.now();
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};
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/**
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@ -56,15 +70,11 @@ Timer.prototype.relativeTime = function () {
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* at the most accurate precision possible.
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*/
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Timer.prototype.start = function () {
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this.startTime = this.relativeTime();
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this.startTime = nowObj.now();
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};
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/**
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* Check time elapsed since `timer.start` was called.
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* @returns {number} Time elapsed, in ms (possibly sub-ms precision).
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*/
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Timer.prototype.timeElapsed = function () {
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return this.relativeTime() - this.startTime;
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return nowObj.now() - this.startTime;
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};
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module.exports = Timer;
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