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In the following code, the "this" keyword references the "myName" object. Why doesn’t the "this" in console.log reference the "window" object, since it is really "window.console.log"?

class Name {
  constructor(firstName) {
    this.firstName = firstName;
  }
  superGreet() {
    console.log('I am', this.firstName);
  }
}
 
let myName = new Name("Jay");
myName.superGreet();
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3

Answers


  1. 0

    Arguments are evaluated in the caller’s scope, not the scope of the function being called. So

      superGreet() {
    console.log('I am', this.firstName);
  }

    is equivalent to

      superGreet() {
    let temp = this.firstName;
    console.log('I am', temp);
  }

    In this rewrite you can see that this is in the scope of myName.superGreet(), not window.console.log(). So this is the value of myName.

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  2. 0

    When console.log('I am', this.firstName); is run, the arguments are evaluated first before calling console.log. Therefore this.firstName is evaluated in the context of the Name object, and the this refers to the Name object.

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  3. 0

    You defined a class called ‘Name’ but instantiated it with ‘Cat’. Assuming you meant to use the correct class name.

    class Name {
  constructor(firstName) {
    this.firstName = firstName;
  }
  superGreet() {
    console.log('I am', this.firstName);
  }
}
 
let myName = new Name("Jay");
myName.superGreet();
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