es6 class 的constructor中如何调用 返回promise 的函数
发布于 3 个月前 作者 chinahsj 332 次浏览 来自 问答
constructor() {
		  this.logObj = null;
		  this.getLogObj();
		  this.log = this.logObj.log;
		  this.trace = this.logObj.trace;
		  this.error = this.logObj.error;
	  }
  
	  getLogObj() {
		  if (!this.logObj) {
			  this.logObj =await this.writeLog();
		  }
		  return this.logObj;
	  }```
上述的代码: 构造中怎么接收 getLogObj函数的值,求帮忙解答 谢谢!
1 回复
  constructor() {
		this.logObj = null;
		this.getLogObj().then(logobj => {
		  this.log = logObj.log;
		  this.trace = logObj.trace;
		  this.error = logObj.error;
		});
  }

不过这样写会有问题,建议log trace error都用getter,或者用一个异步的工厂函数来创建实例

class Foo {
  constructor(cb) {
    this.init().then(() => cb(this));
  }

  async init() {
    const logObj = await this.getLogObj();
    this.log = logObj.log;
    this.trace = logObj.trace;
    this.error = logObj.error;
  }

  getLogObj() {
	return new Promise(r => r(123))
    if (!this.logObj) {
      this.logObj = this.writeLog();
    }
    return this.logObj;
  }
}

function createFoo() {
  return new Promise(res => new Foo(res));
}
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