No.56 要求设计 LazyMan 类，实现以下功能。

题目

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

思路

• 一个class
• 一个taskList
• push任务

• 执行放在marcoTask/miscoTask中

  结果

  ```javascript class Lazy { name; isExec = false; taskList = [];

  constructor(name) { this.name = name; console.log(Hi I am ${name})

}

async exec() { if (this.taskList.length > 0) { console.log(“exec”); await this.taskList.shift()(); setTimeout(() => { this.exec(); }, 0); } else { this.isExec = false; } }

sleepFirst(time) { const fn = function () { return new Promise((res) => { setTimeout(() => { res(); console.log(${time}s gone); }, time * 1000); }); };

console.log("push sleep");
this.taskList.unshift(fn);
return this;

}

sleep(time) { const fn = function () { return new Promise((res) => { setTimeout(() => { res(); console.log(${time}s gone); }, time * 1000); }); };

console.log("push sleep");
this.taskList.push(fn);
return this;

}

eat(name) { const fn = function () { return new Promise((res) => { setTimeout(() => { res(); console.log(I am eating ${name}); }, 1); }); };

console.log("push eat");
this.taskList.push(fn);
if (!this.isExec) {
  this.isExec = true;
  setTimeout(() => {
    console.log("exec --");
    this.exec();
  }, 0);
}
return this;

} }

function LazyMan(name) { return new Lazy(name); }

// LazyMan(“Tony”); // LazyMan(“Tony”).sleep(1).eat(“lunch”); // LazyMan(“Tony”).eat(“lunch”).sleep(3).eat(“dinner”); LazyMan(“Tony”) .eat(“lunch”) .eat(“dinner”) .sleepFirst(5) .sleep(10) .eat(“junk food”);

<a name="FOEDj"></a>
## 优化
```javascript
class Lazy {
  name;
  taskList = [];
  constructor(name) {
    this.name = name;
    console.log(`Hi I am ${name}`);
    setTimeout(() => {
      this.next();
    }, 0);
  }
  next() {
    const fn = this.taskList.shift();
    fn && fn();
  }
  sleepFirst(time) {
    const fn = () => {
      setTimeout(() => {
        console.log(`${time}s gone`);
        this.next();
      }, time * 1000);
    };
    this.taskList.unshift(fn);
    return this;
  }
  sleep(time) {
    const fn = () => {
      setTimeout(() => {
        console.log(`${time}s gone`);
        this.next();
      }, time * 1000);
    };
    this.taskList.push(fn);
    return this;
  }
  eat(name) {
    const fn = () => {
      console.log(`I am eating ${name}`);
      this.next();
    };
    this.taskList.push(fn);
    return this;
  }
}
function LazyMan(name) {
  return new Lazy(name);
}
// LazyMan("Tony");
// LazyMan("Tony").sleep(1).eat("lunch");
// LazyMan("Tony").eat("lunch").sleep(3).eat("dinner");
LazyMan("Tony")
  .eat("lunch")
  .eat("dinner")
  .sleepFirst(5)
  .sleep(10)
  .eat("junk food");