CODEWITHSUNDEEP
javascript
Iditarod1973
Iditarod1973

Reputation: 43

Javascript ".call" don't understand

I don't get the difference between the last 2 lines, specifically the difference between myFunc.call and myFunc. Can someone please explain to me? I'd really appreciate it.

var myObject = {
length: 400,
};

function myFunc () {
return console.log(this.length);

}

myFunc.call(myObject); // equals 400
myFunc(myObject); // equals zero

Upvotes: 0

Views: 46

Answers (2)

Buck Doyle
Buck Doyle

Reputation: 6397

.call() allows you to call a function while specifying what this will refer to inside the function. Calling it without .call uses the current value of this.

In your example, myFunc.call(myObject) runs myFunc with myObject as this, which allows this.length to actually refer to something.

Upvotes: 2

Guffa
Guffa

Reputation: 700302

The call method is used to specify a context for the function, the same as if the function was a member of the object, and was called as a method:

var myObject = {
  length: 400,
  myFunc: function () {
    return console.log(this.length);
  }
};

myObject.myFunc(); // equals 400

Upvotes: 1

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