Javascript Objects: Accessing object variables from methods

Question

Quick question, and one I am yet to work out on my own. I'll start with an example.

object = {
    somevariable: true,
    someothervariable:31,
    somefunction: function(input){
        if (somevariable === true){
            return someothervariable+input;
        }
    }
}

object.somefunction(3);

Obviously this won't work. Do I have to say object.somevariable and object.someothervariable or is there a means of referring to variables that are part of the local object, without referring to the object explicitly?

Thanks

Gausie

outis · Accepted Answer · 2010-01-05 15:35:54Z

5

Use the special keyword this, which refers to the object a function was invoked on:

var thing = {
    somevariable: true,
    someothervariable:31,
    somefunction: function(input){
        if (this.somevariable === true){
            return this.someothervariable+input;
        }
    }
}
thing.somefunction(3);

var otherThing = {
    somevariable: true,
    someothervariable:'foo',
    amethod: thing.somefunction
};
otherThing.amethod('bar');

Be careful about using variable names like "object". JS is case-sensitive, so it won't collide with the intrinsic Object, but you might get into trouble in other languages.

edited Jan 5, 2010 at 15:35

answered Jan 5, 2010 at 15:30

outis

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2 Comments

Gausie Over a year ago

This seems obvious, why did I not try it?

gion_13 Over a year ago

of course, this will work only inside functions... if you have smth like var o = {a:1,b:this.a}; this will definetly won't work

jessegavin · Accepted Answer · 2010-01-05 15:33:25Z

1

When adding "this" it works for me.

var o = {
    somevariable: true,
    someothervariable:31,
    somefunction: function(input){
        if (this.somevariable === true){
            return this.someothervariable+input;
        }
    }
}

alert(o.somefunction(3));

answered Jan 5, 2010 at 15:33

jessegavin

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