创建LazyMan() | 刷题打卡

题目描述

题目地址

思路分析

1. 用构造函数 return this 来实现链式调用

LazyMan('Jack', console.log).eat('banana').eat('apple');

function LazyMan(name, logFn) {
  return new LazyManInstance(name, logFn);
}

2. setTimeout属于异步任务，怎么解决排队呢，可以通过创建一个队列和状态来完成等待，调用每个方法负责添加事件到队列，状态表明可以继续向后执行:

class LazyManInstance {
  eat(value) {
    this.tasks.push({ type: 'eat', payload: value });
    return this;
  }
  sleep(value) {
    this.tasks.push({ type: 'sleep', payload: value });
  }
  
  // 统一状态管理
  next() {
    const task = this.tasks.shift();
    // next 方法就是控制执行的开关
    switch(action) {
      case 'eat':
        console.log(task.payload);
        this.next();
        break;
      case 'sleep':
        setTimeout(() => {
           console.log(task.payload);
           this.next();
           break;
        }, payload * 1000);
    }
  }
}

以上我们就完成了排队，还需要完成 sleepFirst 操作，我们只需要新增一个队列 每次都会在最开始执行的队列 即可：

sleepFirst(time) {
  this.preTask.push('sleep');
  return this;
}

// 先从preTask中找优先执行的任务
next() {
  const task = this.preTask.shift() || this.tasks.shift();
}

AC代码

class LazyManInstance {
  constructor(name, logFn) {
    this.name = name;
    this.log = logFn;
    this.tasks = [];
    this.preTasks = [];
    
    this.init();
    setTimeout(() => {
      this.next()
    }, 0);
  }
  
  init() {
    this.tasks.push({ type: 'init' })
    return this;
  }
  
  eat(value) {
    this.tasks.push({type: 'eat', payload: value});
    return this;
  }
  
  sleep(value) {
    this.tasks.push({type: 'sleep', payload: value});
    return this;
  }
  
  sleepFirst(value) {
    this.preTasks.push({type: 'sleep', payload: value});
    return this;
  }
  
  next() {
    let task = this.preTasks.shift() || this.tasks.shift();
    
    if (!task) {
      return
    }
   
    
    switch (action) {
      case 'init':
        this.log(`Hi, I'm ${this.name}.`);
        this.next();
        break;
      case 'eat':
        this.log(`Eat ${task.value}.`);
        this.next();
        break;
      case 'sleep':
        setTimeout(() => {
          this.log(`Wake up after ${task.type} second.`)
          this.next()
          break;
        }, task.value * 1000);
    }
  }
}

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