animatable-js/src/animation_listenable.ts

This package allows easy and light implementation of linear or curved animation in javascript. (Especially suitable in a development environment on web components or canvas.)

import { Animatable, AnimationStatus } from "./animatable";
import { AnimationListener, AnimationStatusListener } from "./types";

/**
 * This abstract class implements the animation related listener that
 * is called when the current animation value and status changed.
 */
export abstract class AnimationListenable extends Animatable {
    private listeners: AnimationListener[] = [];
    private statusListeners: AnimationStatusListener[] = [];

    /**
     * Registers the given listener that is called when the current
     * animation value changed in this animation instance.
     */
    addListener(listener: AnimationListener) {
        console.assert(!this.listeners.includes(listener), "Already a given listener does exist.");
        this.listeners.push(listener);
    }

    /**
     * Deregisters the given listener that is called when the current
     * animation value changed in this animation instance.
     */
    removeListener(listener: AnimationListener) {
        console.assert(this.listeners.includes(listener), "Already a given listener does not exist.");
        this.listeners = this.listeners.filter(l => l != listener);
    }

    /**
     * Registers the given status listener that is called when the current
     * animation status value changed in this animation instance.
     */
    addStatusListener(listener: AnimationStatusListener) {
        console.assert(!this.statusListeners.includes(listener), "Already a given status listener does exist.");
        this.statusListeners.push(listener);
    }

    /**
     * Deregisters the given status listener that is called when the current
     * animation status value changed in this animation instance.
     */
    removeStatusListener(listener: AnimationStatusListener) {
        console.assert(this.statusListeners.includes(listener), "Already a given status listener does not exist.");
        this.statusListeners = this.statusListeners.filter(l => l != listener);
    };

    /** Notifies a new value updated for a registered animation listeners. */
    notifyListeners(value: number) {
        this.listeners.forEach(l => l(value));
    }

    /** Notifies a new status updated for a registered animation status listeners. */
    notifyStatusListeners(status: AnimationStatus) {
        this.statusListeners.forEach(l => l(status));
    }
}