如何在Meteor方法中的函数中获取this.userId [英] How to get this.userId in function inside Meteor method

问题描述

我需要为每个登录的用户多次调用一个函数，但是当将该函数放置在流星方法内部时，this.userId在函数范围内变为未定义，这是示例:

I need to call a few times a function for every user who is logged in, but when the function is placed inside meteor method, this.userId becomes undefined inside function scope, here's the example:

myMethod: function(){

  console.log(this.userId); // this returns proper userId

  function innerFunction(){
    console.log(this.userId); // this returns undefined
  };
  innerFunction();

}

如何在函数内传递this.userId? 功能是否必须与Meteor.bindEnvironment绑定?

How can I pass this.userId inside a function? Does a function has to be binded with Meteor.bindEnvironment?

推荐答案

您可以使用一些变体来解决此问题:

You have some variants to resolve this:

• 使用.bind()方法:

myMethod: function () {
 console.log(this.userId); // this returns proper userId

 function innerFunction() {
     console.log(this.userId); // this returns undefined
 }

 innerFunction.bind(this);
}

使用.apply()方法将正确的this应用于函数:

use .apply() method for applying correctthis into function:

myMethod: function () {
 console.log(this.userId); // this returns proper userId

 function innerFunction() {
     console.log(this.userId); // this returns undefined
 };

 innerFunction.apply(this);
}

，您也可以只使用this的that来将范围传递到innerFunction中:

also you can just use that insted of thisfor pass the scope into in innerFunction:

myMethod: function () {
    var that = this;
    console.log(this.userId); // this returns proper userId

    function innerFunction() {
       console.log(that.userId); // this returns undefined
    }

    innerFunction();
}

或仅将userId传递到innerFunction

myMethod: function () {
  var userId = this.userId;
  console.log(this.userId); // this returns proper userId

  function innerFunction(userId) {
      console.log(userId); // this returns undefined
  }

  innerFunction();
}

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