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javascriptjquerytypeofobject-literal

Automatically wrapping dynamically added object properties (functions) in a wrapper function

I use this setup to add properties to an object:

var obj = {
    extend: function(key, obj){
        this[key] = obj;
    }
}

This works well. However, in some cases i want to add sub-objects as properties:

obj.extend('new', {
    test: function(){
        console.log('test called');
    }
});

I would like to automatically wrap all functions occurring in the object passed (as second parameter) to obj.extend() in a function which in itself wraps the actual call of the function in $(document).ready(function(){})

My approach was this:

extend: function(key, obj){
    for(var prop in obj){
        if(typeof prop == 'function') {
            console.log(prop + ' is a function'
        } else 
            console.log(prop + ' is NOT a function');
        }
    }
    this[key] = obj;
}

But typeof prop seems to return string and not 'function'. I have checked a variety of articles and posts but the approach:

typeof propertyOfObject == 'function'

seems totally valid.

What am i doing wrong here? Why does typeof propertyOfObject give me 'string'? How can i check if prop is a function?

Solution

  • Because you're just iterating over the Object keys, not its properties.

    You need to fully qualify the property to access it:

    if( typeof obj[ prop ] === 'function' ) { }