31 lines
719 B
JavaScript
31 lines
719 B
JavaScript
|
'use strict';
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Copyright (c) 2013-present, Facebook, Inc.
|
||
|
|
*
|
||
|
|
* This source code is licensed under the MIT license found in the
|
||
|
|
* LICENSE file in the root directory of this source tree.
|
||
|
|
*
|
||
|
|
* @typechecks
|
||
|
|
*/
|
||
|
|
|
||
|
|
var performance = require('./performance');
|
||
|
|
|
||
|
|
var performanceNow;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Detect if we can use `window.performance.now()` and gracefully fallback to
|
||
|
|
* `Date.now()` if it doesn't exist. We need to support Firefox < 15 for now
|
||
|
|
* because of Facebook's testing infrastructure.
|
||
|
|
*/
|
||
|
|
if (performance.now) {
|
||
|
|
performanceNow = function performanceNow() {
|
||
|
|
return performance.now();
|
||
|
|
};
|
||
|
|
} else {
|
||
|
|
performanceNow = function performanceNow() {
|
||
|
|
return Date.now();
|
||
|
|
};
|
||
|
|
}
|
||
|
|
|
||
|
|
module.exports = performanceNow;
|