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实现一个TaskMan,当：

TaskMan('john')/** output:hi, I am john*/

TaskMan('john').doSomething('go to work')/** output:hi, I am johndoSomething go to work*/

TaskMan('john').sleep(3).doSomething('go to work')/** output:hi, I am johnsleeping...0sleeping...1doSomething go to work*/

TaskMan('jianyong').doSomething('go to work').sleep(3).doSomething('go home').sleepFirst(5)/** output:sleep 5 first...sleeping...0sleeping...1sleeping...2sleeping...3hi, I am jianyongdoSomething go to worksleeping...0sleeping...1doSomething go home*/

可以通过一个函数队列实现：

class _TaskMan {        constructor(name) {                this.tasks = []                this.name = name                this.tasks.push(() => {                        console.log('hi, I am ' + this.name)                        this.next()                })                setTimeout(() => this.next(), 0)        }        next() {                let fn = this.tasks.shift()                fn && fn()        }        doSomething(taskname) {                this.tasks.push(() => {                        console.log('doSomething ' + taskname)                        this.next()                })                return this        }        sleep(n) {                this.tasks.push(() => {                        let counter = 0                        let timer = setInterval(() => console.log('sleeping...' + counter++), 1*1000)                        setTimeout(() => {                                this.next()                                clearTimeout(timer)                        }, n*1000)                })                return this        }        sleepFirst(n) {                this.tasks.unshift(() => {                        console.log(`sleep ${n} first...`)                        let counter = 0                        let timer = setInterval(() => console.log('sleeping...' + counter++), 1*1000)                        setTimeout(() => {                                this.next()                                clearTimeout(timer)                        }, n*1000)                })                return this        }}function TaskMan(name) {
           return new _TaskMan(name)}//TaskMan('john')//TaskMan('john').doSomething('go to work')//TaskMan('john').sleep(3).doSomething('go to work')//TaskMan('jianyong').doSomething('go to work').sleep(3).doSomething('go home').sleepFirst(5)