raf-engine/dist/index.js

A js RAF engine

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
;
var RAFEngine = /** @class */ (function () {
    function RAFEngine() {
        var _this = this;
        this.lastRAFId = 0;
        this.frameId = 0;
        this.lastNow = 0;
        this.uidCounter = 0;
        this.stopped = true;
        this.queue = [];
        if (typeof window === 'undefined' || typeof window.requestAnimationFrame === 'undefined') {
            throw new Error("You are not using this package in browser environment");
        }
        this.frameHandler = function () { return _this.frame(); };
    }
    RAFEngine.prototype.start = function () {
        this.stopped = false;
        this.lastNow = performance.now();
        this.lastRAFId = window.requestAnimationFrame(this.frameHandler);
    };
    RAFEngine.prototype.stop = function (force) {
        if (force === void 0) { force = false; }
        if (force) {
            window.cancelAnimationFrame(this.lastRAFId);
        }
        this.stopped = true;
    };
    RAFEngine.prototype.frame = function () {
        var _this = this;
        // Get the distance between this execution and the last
        var now = performance.now();
        var delta = now - this.lastNow;
        this.lastNow = now;
        // Process the que for this frame
        this.queue.forEach(function (fn) {
            if (!fn.isHeavy) {
                fn.handler(delta, _this.frameId);
            }
            else if (_this.frameId % 2 === 0) {
                fn.handler(delta, _this.frameId);
            }
        });
        this.frameId += 1;
        // Continus the loop if not already stopped
        if (!this.stopped) {
            this.lastRAFId = window.requestAnimationFrame(this.frameHandler);
        }
    };
    RAFEngine.prototype.add = function (handler, id, isHeavy) {
        if (isHeavy === void 0) { isHeavy = false; }
        if (typeof handler !== 'function')
            throw new Error("Expected function as handler");
        if (typeof id === 'undefined')
            id = "h_" + ++this.uidCounter;
        this.queue.push({
            id: id,
            handler: handler,
            isHeavy: isHeavy,
        });
        return id;
    };
    RAFEngine.prototype.remove = function (id) {
        if (typeof id === 'undefined')
            throw new Error("Expected id");
        var index = this.queue.findIndex(function (object) { return object.id === id; });
        if (index < 0)
            return;
        else
            this.queue.splice(index, 1);
        if (this.queue.length <= 0)
            this.stop();
    };
    return RAFEngine;
}());
exports.default = RAFEngine;