JavaScript - Array some() Method

Description

Javascript array some() method tests whether some element in the array passes the test implemented by the provided function.

Syntax

Its syntax is as follows −

array.some(callback[, thisObject]);

Parameter Details

callback − Function to test for each element.
thisObject − Object to use as this when executing callback.

Return Value

If some element pass the test, then it returns true, otherwise false.

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 the following code at the top of your script.

if (!Array.prototype.some)
{
   Array.prototype.some = function(fun /*, thisp*/)
   {
      var len = this.length;
      if (typeof fun != "function")
      throw new TypeError();
      
      var thisp = arguments[1];
      for (var i = 0; i < len; i++)
      {
         if (i in this && fun.call(thisp, this[i], i, this))
         return true;
      }
      return false;
   };
}

Example

Try the following example.

<html>
   <head>
      <title>JavaScript Array some Method</title>
   </head>
   
   <body>
   
      <script type="text/javascript">
         if (!Array.prototype.some)
         {
            Array.prototype.some = function(fun /*, thisp*/)
            {
               var len = this.length;
               if (typeof fun != "function")
               throw new TypeError();
               
               var thisp = arguments[1];
               for (var i = 0; i < len; i++)
               {
                  if (i in this && fun.call(thisp, this[i], i, this))
                  return true;
               }
               return false;
            };
         }
         
         function isBigEnough(element, index, array) {
            return (element >= 10);
         }
         
         var retval = [2, 5, 8, 1, 4].some(isBigEnough);
         document.write("Returned value is : " + retval );
         
         var retval = [12, 5, 8, 1, 4].some(isBigEnough);
         document.write("<br />Returned value is : " + retval );
      </script>
      
   </body>
</html>

Output

Returned value is : false
Returned value is : true