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import { AsyncAction } from './AsyncAction';
import { AnimationFrameScheduler } from './AnimationFrameScheduler';
import { SchedulerAction } from '../types';
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
export class AnimationFrameAction<T> extends AsyncAction<T> {
constructor(protected scheduler: AnimationFrameScheduler,
protected work: (this: SchedulerAction<T>, state?: T) => void) {
super(scheduler, work);
}
protected requestAsyncId(scheduler: AnimationFrameScheduler, id?: any, delay: number = 0): any {
// If delay is greater than 0, request as an async action.
if (delay !== null && delay > 0) {
return super.requestAsyncId(scheduler, id, delay);
}
// Push the action to the end of the scheduler queue.
scheduler.actions.push(this);
// If an animation frame has already been requested, don't request another
// one. If an animation frame hasn't been requested yet, request one. Return
// the current animation frame request id.
return scheduler.scheduled || (scheduler.scheduled = requestAnimationFrame(
() => scheduler.flush(null)));
}
protected recycleAsyncId(scheduler: AnimationFrameScheduler, id?: any, delay: number = 0): any {
// If delay exists and is greater than 0, or if the delay is null (the
// action wasn't rescheduled) but was originally scheduled as an async
// action, then recycle as an async action.
if ((delay !== null && delay > 0) || (delay === null && this.delay > 0)) {
return super.recycleAsyncId(scheduler, id, delay);
}
// If the scheduler queue is empty, cancel the requested animation frame and
// set the scheduled flag to undefined so the next AnimationFrameAction will
// request its own.
if (scheduler.actions.length === 0) {
cancelAnimationFrame(id);
scheduler.scheduled = undefined;
}
// Return undefined so the action knows to request a new async id if it's rescheduled.
return undefined;
}
}