How to check if an object is an array?
Posted By: Anonymous
I’m trying to write a function that either accepts a list of strings, or a single string. If it’s a string, then I want to convert it to an array with just the one item so I can loop over it without fear of an error.
So how do I check if the variable is an array?
I’ve rounded up the various solutions below and created a jsperf test. They’re all fast, so just use Array.isArray
— it’s well-supported now and works across frames.
Solution
In modern browsers you can do:
Array.isArray(obj)
(Supported by Chrome 5, Firefox 4.0, IE 9, Opera 10.5 and Safari 5)
For backward compatibility you can add the following:
// only implement if no native implementation is available
if (typeof Array.isArray === 'undefined') {
Array.isArray = function(obj) {
return Object.prototype.toString.call(obj) === '[object Array]';
}
};
If you use jQuery you can use jQuery.isArray(obj)
or $.isArray(obj)
. If you use underscore you can use _.isArray(obj)
.
If you don’t need to detect arrays created in different frames you can also just use instanceof
:
obj instanceof Array
Answered By: Anonymous
Disclaimer: This content is shared under creative common license cc-by-sa 3.0. It is generated from StackExchange Website Network.