i Javascript Array filter() Method
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Javascript Array filter() Method


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Description:

Javascript array filter() method creates a new array with all elements that pass the test implemented by the provided function.

Syntax:

array.filter(callback[, thisObject]);

Here is the detail of parameters:

  • callback : Function to test each element of the array.

  • thisObject : Object to use as this when executing callback.

Return Value:

Returns created array.

Compatibility:

This method is a JavaScript extension to the ECMA-262 standard; as such it may not be present in other implementations of the standard. To make it work you need to add following code at the top of your script:

if (!Array.prototype.filter)
{
  Array.prototype.filter = function(fun /*, thisp*/)
  {
    var len = this.length;
    if (typeof fun != "function")
      throw new TypeError();

    var res = new Array();
    var thisp = arguments[1];
    for (var i = 0; i < len; i++)
    {
      if (i in this)
      {
        var val = this[i]; // in case fun mutates this
        if (fun.call(thisp, val, i, this))
          res.push(val);
      }
    }

    return res;
  };
}

Example:

<html>
<head>
<title>JavaScript Array filter Method</title>
</head>
<body>
<script type="text/javascript">
if (!Array.prototype.filter)
{
  Array.prototype.filter = function(fun /*, thisp*/)
  {
    var len = this.length;
    if (typeof fun != "function")
      throw new TypeError();

    var res = new Array();
    var thisp = arguments[1];
    for (var i = 0; i < len; i++)
    {
      if (i in this)
      {
        var val = this[i]; // in case fun mutates this
        if (fun.call(thisp, val, i, this))
          res.push(val);
      }
    }

    return res;
  };
}

function isBigEnough(element, index, array) {
  return (element >= 10);
}

var filtered  = [12, 5, 8, 130, 44].filter(isBigEnough);
document.write("Filtered Value : " + filtered ); 
  
</script>
</body>
</html>

This will produce following result:

Filtered Value : 12,130,44 

To understand it in better way you can Try it yourself.



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