4.实现可以链式调用的延时

[conan1992]

Person("Smith").sleepFirst(5).eat("supper");
// 输出：
// 等待5秒
// Wake up after 5
// Hi This is Smith!
// Eat supper

1.分析

1).链接所有 this;

2).把所有任务放到任务队列里面;

3).通过一个方法有序执行队列里面的任务;

2.实现

function person(name){
    return new Person(name);
}
function Person(name){
    this.tasks = [];
    this.tasks.push(()=>{
        console.log('Hi!This is '+name+'.');
        this.then();
    });
    setTimeout(()=>{
        this.then();
    })
}
Person.prototype.eat = function( name ){
    this.tasks.push(()=>{
        console.log('Eat '+name+'.');
        this.then();
    })
    return this;
}
Person.prototype.sleep = function( time ){
    this.tasks.push( ()=>{
        console.log('等待 '+time+'秒.');
        setTimeout(()=>{
            console.log('wake up after '+time+'seconds.');
            this.then();
        },time*1000)
    });
    return this;
}
Person.prototype.sleepFirst = function( time ){
    this.tasks.unshift( ()=>{
        console.log('等待 '+time+'秒.');
        setTimeout(()=>{
            console.log('wake up after '+time+'seconds.');
            this.then();
        },time*1000)
    });
    return this;
}
Person.prototype.then = function(){
    let task = this.tasks.shift();
    task && task();
    return this;
}

3.测试

person("Smith").sleepFirst(5).eat("lunch").sleep(3).eat('cake');