Javascript : use string to invoke function

Question

My question is quite simple. In Php you can call a function including a string in the name of your function. Example :

function setName(name){
    $this->name = name;
}

$string = 'Name';
$method = 'set'.$string;
if(method_exists($this, $method)
    $this->$method($_POST['name']);

So I wanted to know if there was something like this in Javascript... For now, I'm using a switch to check the body id and call the function. This is my code :

switch($('body').attr('id'))
{
    case 'index':
        app.index.init();
        break;
    case 'login':
        app.login.inint();
        break;
};

app.index = {
    init : function(){
        console.log('Hola Mundo');
    }
};

So I was wondering if I could make something like this :

var id = $('body').attr('id');
app.id.init();

thanks for your answers.

You could do that, app is an object and you can reference a property by a string held in a variable via app[myVar]. However it's less secure than using a switch with definite function names defined. — James
– James, Commented Aug 10, 2017 at 22:48

Manuel Otto · Accepted Answer · 2017-08-10 22:50:12Z

2

Yes.

app[id].init();

But consider that this might cause an error if the id of your body is not defined in the app object, as James already pointed out.

answered Aug 10, 2017 at 22:50

Manuel Otto

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Comments

asmmahmud · Accepted Answer · 2017-08-10 23:07:43Z

0

It can be done. You don't have to check it in switch. As id attribute is a string value so you can check directly property existence using objectInstance[prop] way and if it exists then you can invoke it safely:

app.index = {
    init : function(){
        console.log('Hola Mundo');
    }
};
app.login = {
    init : function(){
        console.log('Hola Mundo');
    }
};
var appProp = $('body').attr('id'); /* or var id = $('body').id; */
if(app[appProp]){
   app[appProp].init();
}

answered Aug 10, 2017 at 23:07

asmmahmud

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1 Comment

Simon Trichereau Over a year ago

Work like a charm! Thanks you a lot! :)

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