Javascript Function object call() in NODEJS

Question

I have read through call() method and wondering on the global output below. Shouldnt it be this.name where in this case "Michael". However the output displayed is undefined.

---NEW INFORMATION : THIS IS RUNNING THROUGH NODEJS---

function sayNameForAll(label) {
console.log(label + ":" + this.name);
 }

var person1 = {
name: "Nicholas"
};

var person2 = {
name: "Greg"
};

var name = "Michael";

sayNameForAll.call(this,"global");  //ouput global:undefined
sayNameForAll.call(person1,"PersonName1"); //PersonName1:Nicholas
sayNameForAll.call(person2,"PersonName2"); //PersonName2:Greg

How do you call this code? Are you sure you're in a global scope? It works as expected: jsfiddle.net/7pxsh8gh — zerkms
– zerkms, Commented Mar 10, 2015 at 8:26

Madara's Ghost · Accepted Answer · 2015-03-10 08:33:55Z

2

The reason is probably that in this context, this is not the same scope. This can happen because of several reasons:

You're running this in a function (even a (function() { self invoking function })())
You're running this in nodejs and not in the browser, in node, in the global scope, this is undefined as opposed to window in the browser.

edited Mar 10, 2015 at 8:33

answered Mar 10, 2015 at 8:28

Madara's Ghost

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2 Comments

Madara's Ghost Over a year ago

@zerkms Because in the global scope in node, this is undefined as opposed to window in the browser.

FRizal Over a year ago

oh yes i am running on nodejs...How could this explain

JLRishe · Accepted Answer · 2015-03-10 08:27:26Z

0

Works fine here (click Run Snippet).

Is your code running inside another function? If it is, then the variables you declare would not be on the global object and depending on how you are invoking the function, this might not refer to the global object.

function sayNameForAll(label) {
    console.log(label + ":" + this.name);
}

var person1 = {
    name: "Nicholas"
};

var person2 = {
    name: "Greg"
};

var name = "Michael";

sayNameForAll.call(this,"global");  //ouput global:undefined
sayNameForAll.call(person1,"PersonName1"); //PersonName1:Nicholas
sayNameForAll.call(person2,"PersonName2"); //PersonName2:Greg

answered Mar 10, 2015 at 8:27

JLRishe

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1 Comment

FRizal Over a year ago

Because in the global scope in node, this is undefined as opposed to window in the browser. – Second Rikudo

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