任务调动

异步并行

几个异步同时执行，最后一个执行完毕调用一下回调方法

• 原生JavaScript

当多个任务要串行执行，结果要统一处理时，将多个任务放入队列中执行，直到所有任务结束才结束，一分钟执行60次

var mQueue = function () {
    this.fnSources = [];
    this.excuting = false; 
    this.add = function (fn) {
        if (typeof fn !== "function")
            throw ("第一个参数必须是方法");
        var args = Array.from(arguments).splice(1);
        this.fnSources.push({
            fn: fn,
            args: args
        })
    };
    this.addWithContext = function (context,fn) {
        if (typeof fn !== "function")
            throw ("第二个参数必须是方法");
        var args = Array.from(arguments).splice(2);
        this.fnSources.push({
            fn: fn,
            args: args,
            context:context
        })
    };
    this.clear = function () {
        this.fnSources = [];
        this.excuting = false;
    }
    this.next = function () {
        if (this.excuting){
            return;
        }
        var fnObj = this.fnSources.splice(0, 1)[0];
        if (fnObj) {
            // console.log('next:'+this.excuting)
            this.excuting = true;
            fnObj.args.unshift(this);
            fnObj.fn.apply(fnObj.context, fnObj.args);
        }
    }
    this.finished = function () {
     // console.log('finished')
        this.excuting = false;
    }
    var that = this;
    setInterval(function () {
        that.next();
    }, 1000 / 60)
}
module.exports = mQueue

• 用class方法

class AsyncSerial{
    constructor() {
        this.cbList = [];
    }
    tap(fn) {
        this.cbList.push(fn);
    }
    call(end){
        let index = 0;
        let next = () => {
            if(index === this.cbList.length){
                end();
                return;
            }
            let fn = this.cbList[index];
            fn(() => {
                index++;
                next();
            })
        }
        next();
    }
}
let ap = new AsyncSerial();
ap.tap((cb) => {
    setTimeout(() => {
        console.log(1);
        cb();
    }, 3000)
})
ap.tap((cb) => {
    setTimeout(() => {
        console.log(3);
        cb();
    }, 2000)
});
ap.call(() => {
    console.log('end');
})

异步并行

class AsyncParallel {
    constructor() {
        this.cbList = [];
    }
    tap(fn) {
        this.cbList.push(fn);
    }
    call(end) {
        let index = 0;
        this.cbList.forEach(fn => {
            fn(() => {
                index++;
                if (index === this.cbList.length) { end() };
            });
        })
    }
}
let ap = new AsyncParallel();
ap.tap((cb) => {
    setTimeout(() => {
        console.log(1);
        cb();
    }, 3000)
})
ap.tap((cb) => {
    setTimeout(() => {
        console.log(3);
        cb();
    }, 1000)
});
ap.call(() => {
    console.log('end');
})