Kanishka Panamaldeniya Kanishka Panamaldeniya - 5 months ago 122
Javascript Question

is there an equalant to PHP array_key_exists in javascript or jquery


Possible Duplicate:

Checking if an associative array key exists in Javascript




I have a PHP code block . For a purpose I am converting this to a JavaScript block.

I have PHP

if(array_key_exists($val['preferenceIDTmp'], $selected_pref_array[1]))


now I want to do this in jQuery. Is there any built in function to do this?

Answer

Note that objects (with named properties) and associative arrays are the same thing in javascript.

You can use hasOwnProperty to check if an object contains a given property:

o = new Object();  
o.prop = 'exists'; // or o['prop'] = 'exists', this is equivalent 

function changeO() {  
  o.newprop = o.prop;  
  delete o.prop;  
}  

o.hasOwnProperty('prop');   //returns true  
changeO();  
o.hasOwnProperty('prop');   //returns false  

Alternatively, you can use:

if (prop in object)

The subtle difference is that the latter checks the prototype chain.