CODEWITHSUNDEEP
javascript
Ben
Ben

Reputation: 2269

How can I call a function inside of a function?

How can I call the function inside of this function?

var video = function() {

    this.name = "Name of Video";
    this.desc = "Short Description of Video";
    this.long = "Long Description of Video";

    function metadata(){
        return {
            name : this.name,
            shortDescription : this.desc,
            longDescription : this.long
        };
    };

};

Upvotes: 3

Views: 167

Answers (4)

Mik378
Mik378

Reputation: 22171

You can't reach a nested function from the outside of the first outer wrapping-function directly:

See more info about that here: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions_and_function_scope

Therefore, an easy solution would be to use a function expression, attached to the returned object.

var video = function() {

    this.name = "Name of Video";
    this.desc = "Short Description of Video";
    this.long = "Long Description of Video";

    this.metadata = function(){
        return {
            name : this.name,
            shortDescription : this.desc,
            longDescription : this.long
        };
    };
};

new video().metadata();

Upvotes: 1

Travis J
Travis J

Reputation: 82267

jsFiddle Demo

There are several options. A highly used approach is prototypes. A prototype will extend the object created with the functions defined on the prototype if the new keyword is used. You can take advantage of this to expose functions.

var video = function() {
 if( !(this instanceof video) ){//ensure that we always work with an instance of video
  return new video();   
 }

 this.name = "Name of Video";
 this.desc = "Short Description of Video";
 this.long = "Long Description of Video";
};
video.prototype.metadata = function(){
 return {
    name : this.name,
    shortDescription : this.desc,
    longDescription : this.long
 };
};

Now the options, it can be called directly:

console.log(video().metadata());

It can be used as a function call and then referenced

var v = video();
console.log(v.metadata());

Or it can be explicitly instantiated and then referenced

var vid = new video();
console.log(vid.metadata());

This ensures that basically all uses of the function end up with the same functionality.

Upvotes: 4

Igor
Igor

Reputation: 15893

Make it a method of the new object:

var video = function() {

    this.name = "Name of Video";
    this.desc = "Short Description of Video";
    this.long = "Long Description of Video";

    this.metadata = function(){
        return {
            name : this.name,
            shortDescription : this.desc,
            longDescription : this.long
        };
    };
};

var videoObject = new video();
videoObject.metadata();

Upvotes: 8

Kevin B
Kevin B

Reputation: 95031

You can't, other than within said function.

var video = function() {

    this.name = "Name of Video";
    this.desc = "Short Description of Video";
    this.long = "Long Description of Video";

    function metadata(){
        return {
            name : this.name,
            shortDescription : this.desc,
            longDescription : this.long
        };
    };
    metadata();

};

Upvotes: 5

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