angular2
Version:
Angular 2 - a web framework for modern web apps
72 lines (71 loc) • 2.87 kB
JavaScript
import { ApplicationRef } from 'angular2/src/core/application_ref';
import { isPresent, NumberWrapper } from 'angular2/src/facade/lang';
import { window } from 'angular2/src/facade/browser';
import { DOM } from 'angular2/src/platform/dom/dom_adapter';
export class ChangeDetectionPerfRecord {
constructor(msPerTick, numTicks) {
this.msPerTick = msPerTick;
this.numTicks = numTicks;
}
}
/**
* Entry point for all Angular debug tools. This object corresponds to the `ng`
* global variable accessible in the dev console.
*/
export class AngularTools {
constructor(ref) {
this.profiler = new AngularProfiler(ref);
}
}
/**
* Entry point for all Angular profiling-related debug tools. This object
* corresponds to the `ng.profiler` in the dev console.
*/
export class AngularProfiler {
constructor(ref) {
this.appRef = ref.injector.get(ApplicationRef);
}
/**
* Exercises change detection in a loop and then prints the average amount of
* time in milliseconds how long a single round of change detection takes for
* the current state of the UI. It runs a minimum of 5 rounds for a minimum
* of 500 milliseconds.
*
* Optionally, a user may pass a `config` parameter containing a map of
* options. Supported options are:
*
* `record` (boolean) - causes the profiler to record a CPU profile while
* it exercises the change detector. Example:
*
* ```
* ng.profiler.timeChangeDetection({record: true})
* ```
*/
timeChangeDetection(config) {
var record = isPresent(config) && config['record'];
var profileName = 'Change Detection';
// Profiler is not available in Android browsers, nor in IE 9 without dev tools opened
var isProfilerAvailable = isPresent(window.console.profile);
if (record && isProfilerAvailable) {
window.console.profile(profileName);
}
var start = DOM.performanceNow();
var numTicks = 0;
while (numTicks < 5 || (DOM.performanceNow() - start) < 500) {
this.appRef.tick();
numTicks++;
}
var end = DOM.performanceNow();
if (record && isProfilerAvailable) {
// need to cast to <any> because type checker thinks there's no argument
// while in fact there is:
//
// https://developer.mozilla.org/en-US/docs/Web/API/Console/profileEnd
window.console.profileEnd(profileName);
}
var msPerTick = (end - start) / numTicks;
window.console.log(`ran ${numTicks} change detection cycles`);
window.console.log(`${NumberWrapper.toFixed(msPerTick, 2)} ms per check`);
return new ChangeDetectionPerfRecord(msPerTick, numTicks);
}
}