Possible Duplicate:
How to detect if a variable is an array
When I need to test if variable is an array (for example input argument in a function that could be object or array) I usually use this piece of code
typeof(myVar) === 'object' && myVar.length !== undefined;
Is this the correct way or is there a more efficient way, considering that even if myVar instanceof Array is faster it should be avoided due to iframe problem?
Array.isArray is now available with ECMAScript 5, so you can use it with a polyfill for older browsers:
if(!Array.isArray) {
Array.isArray = function (vArg) {
return Object.prototype.toString.call(vArg) === "[object Array]";
};
}
Array.isArray(myVar);
The "iframe problem` can be avoided simply by not using the same name for a frame and for an array. Not hard to do, in my opinion. That said, I've never had a need to assert whether or not something is an array...
If you are already using jQuery within your code, you may use jQuery.isArray(). Here is the documentation:
You can try - Object.prototype.toString.call
An example -
var a = [1,2]
console.log(Object.prototype.toString.call(a))
This returns [object Array]
which can be checked with string slice method in following way
console.log(Object.prototype.toString.call(a).slice(8,-1)) <br />
which returns "Array"
var a = [1,2]
console.log(Object.prototype.toString.call(a).slice(8,-1) == "Array") // true
'[object Array]' (like below)
function isArray(value) { return value instanceof Array }src