How to convert a string to an object?

Question

I preload load two different images at the top of my javascript file.

var imgColor = new Image();
var imgLoadedColor = false;
imgColor.src = 'color/progress.png';

imgColor.onload = function(){
  imgLoadedColor = true;
}   

var imgBlackWhite = new Image();
var imgLoadedColor = false;
imgBlackWhite.src = 'blackWhite/progress.png';

imgBlackWhite.onload = function(){
  imgLoadedColor = true;
}

The string in this.options.type is either imgColor or imgBlackWhite.

When I try to pass the argument this.options.type to a function, I get an error because the value in this.options.type is a string, not an object. However if I pass the argument imgColor it loads the colored image and if I pass the argument imgBlackWhite it loads the black and white image because imgColor and imgBlackWhite are objects.

How do I create a reference to the objects imgColor and imgBlackWhite from the value of the string in this.options.type?

Need more code. What does the function your passing `this.options.type` look like? — Loktar, Apr 08 '12 at 23:54

score 1 · Accepted Answer · edited May 23 '17 at 11:56

1

Why not just use an if statement?

if (arg == "imgColor") return imgColor;
else return imgBlackWhite;

EDIT: you can also use new windowtypename to instantiate an object (per this thread: Instantiate a JavaScript Object Using a String to Define the Class Name). So, instead of the above:

return new window[arg]();

edited May 23 '17 at 11:56

Community

1
1

answered Apr 08 '12 at 23:55

McGarnagle

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score 0 · Answer 2 · answered Apr 09 '12 at 00:01

0

Pass the argument:

this[this.options.type]

answered Apr 09 '12 at 00:01

Paul

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How to convert a string to an object?

2 Answers2