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JavaScript String.prototype.doStuff new function is never defined

P

ppowell777

Well-Known Coder
prototypes.js:

JavaScript: 
if (!String.prototype.doStuff) {
    String.prototype.doStuff = (str) => {
        // do stuff to this with str
        return this.substring(0, this.length());
    };

alert(typeof doStuff); // returns "undefined" and I don't know why
}

index.html:

HTML: 
<html>
    <head>
        <script src="scripts/prototypes.js"></script>
    </head>
    <body>
        Blah blah blah..
        <!-- STUFF -->
    </body>
</html>

This very simple code somehow fails, and I don't know why. I want to be able to run myString.doStuff(str), but the function is never defined within the String prototype. I honestly have never had this problem in the past. Please help, as this is breaking an entire website.

Thanks
 
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Try alert(String.prototype.doStuff) or alert("help".doStuff). It is attached to String and therefore can only be accessed either on a String or it's prototype. Also for defining, in an if (typeof String.prototype.doStuff == "undefined") thing should work. X E.
 
Last edited:
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