bluebird on Google Closure: How not to write Javascript

Comment on Google Closure: How not to write Javascript

Hey,

goog.isString = function(val) { return typeof val == 'string'; };

var b = new String("I am also a string!"); alert(goog.isString(b)); // Will output FALSE

If that doesn't scream ignorance of the language, what does?

For reference for anyone else who doesn't know how this should be done correctly (I had to go and look at the dojo source).

    dojo.isString = function(/*anything*/ it){
        // summary:
        // Return true if it is a String
        return (typeof it == "string" || it instanceof String); // Boolean
    }

dgreensp 16y

I write a lot of JavaScript and I'm not even sure this is preferable. The "object wrappers" like String are considered deprecated in some circles as a matter of style, e.g. by Crockford. From this point of view, a stricter check is cleaner. And contrary to what the article implies, String(foo) is a cast to a primitive string, and doesn't create an object like 'new String' does.

So the Google function correctly returns whether String(foo) is a no-op.

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