jQuery isArray() Method

What Is isArray()?

jQuery.isArray(obj) (alias $.isArray) returns true when obj is a true JavaScript Array (since jQuery 1.3). Array-like objects are not arrays.

$.isArray(obj)  → true | false

$.isArray([])           // true
$.isArray({})           // false
$.isArray($("div"))     // false  (jQuery collection)
$.isArray("hi")         // false

// Prefer in new code:
Array.isArray([])       // true

How to Use isArray()

Pass any value; branch on the boolean result — or migrate to native.

1. Have a value of unknown type (API data, option, argument).
2. Call $.isArray(value) (legacy) or Array.isArray(value) (preferred).
3. If true, treat it as a real array (.map, $.grep, etc.).
4. If array-like but not an array, convert with $.makeArray() first.

Pseudocode

function isArray(obj):
    // true only for real Array instances
    // false for {}, NodeList, jQuery, arguments, strings…
    return Array.isArray(obj)   // what modern jQuery uses

// Typical guard:
if isArray(data):
    process as array
else if array-like:
    data = makeArray(data)
else:
    handle non-list

Cheat Sheet

Keep these facts handy while checking array types.

Live Preview

Test common values with $.isArray (and see the native twin).

value = []
$.isArray(value) → true
Array.isArray(value) → true

jQuery Examples

Short, copy-ready snippets. Open DevTools Console, or use Try It Yourself for a live editor.

console.log($.isArray([]));  // true
console.log($.isArray({}));  // false

true
false

var $els = $("body");
var real = [1, 2, 3];

console.log($.isArray($els));  // false
console.log($.isArray(real));  // true
console.log($els.length);      // 1 (array-like, still not an Array)

false
true
1

console.log(typeof []);           // "object"
console.log(typeof {});           // "object"
console.log($.isArray([]));       // true
console.log($.isArray({}));       // false

object
object
true
false

console.log($.isArray([1, 2]));       // true
console.log(Array.isArray([1, 2]));   // true

console.log($.isArray("nope"));       // false
console.log(Array.isArray("nope"));   // false

true
true
false
false

Performance Notes

Array checks are cheap. Prefer the native call for clarity and to avoid a removed jQuery API — not for micro-speed gains.

Key Takeaways