Home/ Questions/Q 6071863
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-23T10:05:45+00:00

I am trying to implement (so-to-say) a refinement in JavaScript. Kindly look at the

  • 0

I am trying to implement (so-to-say) a refinement in JavaScript. Kindly look at the following example:

<html>
<head>
<title>Function Override (Refinement) example</title>
<script type="text/javascript">

// original function
function oneFunc() {
    document.writeln("<p> In original oneFunc() </p>");
}

var prevOneFunc = null;
if (oneFunc) {
    prevOneFunc = oneFunc;
}

// redeclared function (should refine/complement the original one)
function oneFunc() { 
    if (prevOneFunc) {
        prevOneFunc(); // should call original oneFunc(), BUT IT ISN'T
    }
    document.writeln("<p> In refined oneFunc() </p>");
}

oneFunc();

</script>
</head>
<body>
</body>
</html>

My intention was to have two printouts:

In original oneFunc()
In refined oneFunc()

However, it seems that since at the moment of execution oneFunc refers to the new/refined function, hence the output is different than expected. In the debugger checked that I am entering into the infinite recursion 🙂 (yes, understood why exactly).

Please explain which information I am missing to implement it properly.

Update: A few limitations: I think (not sure) that I can’t modify the original oneFunc declaration and it is declared just like described above. I shouldn’t modify the declaration of the refined oneFunc either.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    That is because of JavaScript hoisting.
    http://www.adequatelygood.com/2010/2/JavaScript-Scoping-and-Hoisting

    Try this:

    
var oneFunc = function(){ 
//In original oneFunc 
};

var prevOneFunc = null;
if (oneFunc) {
    prevOneFunc = oneFunc;
}

oneFunc = function(){
//In refined oneFunc 
};

oneFunc();
    • 0