How to Achieve PHP's `in_array()` Functionality in JavaScript?

JavaScript Alternative to PHP's in_array()

In JavaScript, there is no built-in function that behaves exactly like PHP's in_array(). However, popular libraries offer utility functions to achieve similar functionality.

jQuery's inArray function follows PHP's behavior and compares values within arrays:

function inArray(needle, haystack) {
  var length = haystack.length;
  for (var i = 0; i < length; i++) {
    if (haystack[i] == needle) return true;
  }
  return false;
}

If you need to check if an array is within another array, like PHP's in_array(), a custom function like the following is needed:

function inArrayNested(needle, haystack) {
  var length = haystack.length;
  for (var i = 0; i < length; i++) {
    if (typeof haystack[i] == 'object') {
      if (arrayCompare(haystack[i], needle)) return true;
    } else {
      if (haystack[i] == needle) return true;
    }
  }
  return false;
}

This function inArrayNested checks both simple and nested arrays. Remember that extending the Array prototype is generally not recommended.

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