JavaScript returns function not value

Question

I have an object from which I call a function. Instead of the value it returns the function itself. This might be a duplicate but I could not find a proper solution. So any buzzword for this matter would be highly appreciated.

var w = window,
    d = document,
    e = d.documentElement,
    g = d.getElementsByTagName('body')[0];

var asd = {
    getWindowWidth: function() {
        var x = w.innerWidth || e.clientWidth || g.clientWidth;
        return x;
    },
    getWindowHeight: function() {
        var x = (function() {
            return w.innerWidth || e.clientWidth || g.clientWidth;
        })();
        return x;
    },
    init: function() {
        console.log("init fired");
        console.log(this.getWindowWidth);
        console.log(this.getWindowHeight);
        console.log(typeof(this.getWindowHeight));
    }
}

asd.init();

Thank you in advance for your support.

Well console.log(this.getWindowWidth); returns the function console.log(this.getWindowWidth()); evaluates it and returns the result if thats what you asking (which is not very clear). — Alex K.
– Alex K., Commented May 30, 2017 at 10:03
"I have an object from which I call a function" — No, you don't. You have an object from which you console.log a function. You have to put () after a pointer to a function to actually call it. — Quentin
– Quentin, Commented May 30, 2017 at 10:04

MrCode · Accepted Answer · 2017-05-30 10:04:19Z

3

Use parenthesis to call the function, otherwise you have simply captured the function itself.

console.log(this.getWindowWidth());
//                             ^^

answered May 30, 2017 at 10:04

MrCode

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Comments

Mohideen bin Mohammed · Accepted Answer · 2017-05-30 10:10:57Z

2

Simply change your function like this, this.getWindowWidth()

without paranthesis it will do actual function call and it wont return a value.

var w = window,
    d = document,
    e = d.documentElement,
    g = d.getElementsByTagName('body')[0];

var asd = {
    getWindowWidth: function() {
        var x = w.innerWidth || e.clientWidth || g.clientWidth;
        return x;
    },
    getWindowHeight: function() {
        var x = (function() {
            return w.innerWidth || e.clientWidth || g.clientWidth;
        })();
        return x;
    },
    init: function() {
        console.log("init fired");
        console.log(this.getWindowWidth());
        console.log(this.getWindowHeight());
        console.log(typeof(this.getWindowHeight()));
    }
}

asd.init();

edited May 30, 2017 at 10:10

answered May 30, 2017 at 10:04

Mohideen bin Mohammed

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Comments

EstevaoLuis · Accepted Answer · 2017-05-30 10:05:22Z

0

You are using this.getWindowHeight instead of this.getWindowHeight()

var w = window,
    d = document,
    e = d.documentElement,
    g = d.getElementsByTagName('body')[0];

var asd = {
    getWindowWidth: function() {
        var x = w.innerWidth || e.clientWidth || g.clientWidth;
        return x;
    },
    getWindowHeight: function() {
        var x = (function() {
            return w.innerWidth || e.clientWidth || g.clientWidth;
        })();
        return x;
    },
    init: function() {
        console.log("init fired");
        console.log(this.getWindowWidth());
        console.log(this.getWindowHeight());
        console.log(typeof(this.getWindowHeight()));
    }
}

asd.init();

answered May 30, 2017 at 10:05

EstevaoLuis

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Comments

Ionut Ungureanu · Accepted Answer · 2017-05-30 10:09:44Z

the init function is invoked, but the other functions not so much. As Alex K. said you need to change

console.log(this.getWindowWidth);
console.log(this.getWindowHeight);
console.log(typeof(this.getWindowHeight));

to:

console.log(this.getWindowWidth());
console.log(this.getWindowHeight());
console.log(typeof(this.getWindowHeight()));

var w = window,
    d = document,
    e = d.documentElement,
    g = d.getElementsByTagName('body')[0];

var asd = {
    getWindowWidth: function() {
        var x = w.innerWidth || e.clientWidth || g.clientWidth;
        return x;
    },
    getWindowHeight: function() {
        var x = (function() {
            return w.innerWidth || e.clientWidth || g.clientWidth;
        })();
        return x;
    },
    init: function() {
        console.log("init fired");
        console.log(this.getWindowWidth());
        console.log(this.getWindowHeight());
        console.log(typeof(this.getWindowHeight()));
    }
}

asd.init();

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