LazyMan('Tony');
// Hi I am Tony
LazyMan('Tony').sleep(10).eat('lunch');
// Hi I am Tony
// 等待了10秒...
// I am eating lunch
LazyMan('Tony').eat('lunch').sleep(10).eat('dinner');
// Hi I am Tony
// I am eating lunch
// 等待了10秒...
// I am eating diner
LazyMan('Tony').eat('lunch').eat('dinner').sleepFirst(5).sleep(10).eat('junk food');
// Hi I am Tony
// 等待了5秒...
// I am eating lunch
// I am eating dinner
// 等待了10秒...
// I am eating junk food
class LazyManClass {
constructor(name) {
this.taskList = []
this.name = name
console.log(`I am ${this.name}`)
setTimeout(()=>{ //设置宏任务，等待eat，sleep等函数被调用之后再触发next
this.next()
},0)
}
eat(name) {
let that = this
let fn = (function (name) {
return function() {
console.log(`I eat ${name}`)
that.next()
}
})(name)
this.taskList.push(fn)
return this
}
sleepFirst(time) {
let that = this
let fn = (function(time) {
return function() {
setTimeout(()=>{
console.log(`sleep first ${time}`)
that.next()
}, time*1000)
}
})(time)
this.taskList.unshift(fn)
return this
}
sleep(time) {
let that = this
let fn = (function(time) {
return function() {
setTimeout(()=>{
console.log(`sleep ${time}`)
that.next()
},time*1000)
}
})(time)
this.taskList.push(fn)
return this
}
next() {
let fn = this.taskList.shift()
fn && fn()
}
}
function LazyMan(name) {
return new LazyManClass(name)
}
LazyMan('Tony').eat('lunch').eat('dinner').sleepFirst(5).sleep(10).eat('junk food')
/* I am Tony
sleep first 5
I eat lunch
I eat dinner
sleep 10
I eat junk food*/
题目：实现LazyMan
解题思路：主要思想就是采用一个taskList数组记录事件触发函数以及触发的顺序，eat是按照顺序push进数组，sleepFirst是unshift，sleep也是按顺序push。在构造方法中通过添加宏任务，使得最后调用next函数，一一触发之前记录的事件。