CODEWITHSUNDEEP
javascript
Adam Lee
Adam Lee

Reputation: 25768

Any difference between those two in Javascript?

Using this

var Class1 = function() {       
        this.test1 = function() {
        };
    };

and the following

function Class1() { 
};

Class1.prototype.test1 = function() {

};

Is there difference between those two?

Upvotes: 2

Views: 85

Answers (4)

Katti
Katti

Reputation: 2121

Using the later one in efficient.

Functions in JavaScript are objects. Every object in JavaScript holds a hidden piece of state – a reference to another object known as the object’s prototype.

Using prototype multiple objects can maintain references to the same prototype object.

This is a great reference to know how prototype in js works.

Upvotes: 0

Bergi
Bergi

Reputation: 665122

Yes, there are. See

for the two (independent) differences.

Upvotes: 0

Sarfraz
Sarfraz

Reputation: 382831

There is difference which affects performance as well.

The first one will add function to each instance of the created class while latter won't. For the latter method, JavaScript will look into prototype chain of the object and would return the needed method, the test1 in your case.

Upvotes: 0

SLaks
SLaks

Reputation: 887867

The first one makes a separate copy of the function for each class instance.
It also allows the function to use closure'd variables from the constructor.

Upvotes: 3

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