How do I check if a variable is an array in JavaScript?
Apr 10, 2022 · There are several ways of checking if an variable is an array or not. The best solution is the one you have chosen. This is the fastest method on Chrome, and most likely all other browsers. All arrays are objects, so checking the constructor property is a fast process for JavaScript engines.
javascript - Difference between using Array.isArray and instanceof ...
Mar 10, 2014 · Difference between Array.isArray(item) and item instanceof Array. As Felix Kling mentioned in the comment, instanceof Array doesn't work across iframes. To give you a specific example, try the following code:
javascript - How can I check if an object is an array ... - Stack Overflow
If you use jQuery you can use jQuery.isArray(obj) or $.isArray(obj). If you use Underscore.js 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
instanceof considered harmful or how to write a robust isArray ...
Jan 10, 2009 · function isArray(o) { return Object.prototype.toString.call(o) === '[object Array]'; } The solution is not dependent on frames (since it checks internal [[Class]]) and is more robust than duck-typing approach.
instanceof - JavaScript | MDN - MDN Web Docs
Mar 13, 2025 · For instance, you can securely check if a given object is in fact an Array using Array.isArray(), neglecting which realm it comes from. For example, to check if a Node is an SVGElement in a different context, you can use myNode instanceof myNode.ownerDocument.defaultView.SVGElement.
Array.isArray() - JavaScript | MDN - MDN Web Docs
Mar 5, 2025 · Array.isArray() checks if the passed value is an Array. It performs a branded check, similar to the in operator, for a private property initialized by the Array() constructor. It is a more robust alternative to instanceof Array because it avoids false positives and false negatives:
How to Check If a Variable is an Array in JavaScript - JavaScript …
This tutorial shows you how to use the Array.isArray() method and instanceof operator to check if a variable is an array in JavaScript
How do I check if a variable is an array in JavaScript?
Determining whether a variable is an array is a fundamental task in JavaScript. Whether you’re filtering API data, validating function arguments, or simply writing defensive code, it’s essential to distinguish arrays from other data types.
Using JavaScript to Determine if a Variable is an Array - Medium
Determining whether a variable is an array in JavaScript is essential for writing robust and error-free code. By using methods like Array.isArray(), instanceof, and...
JavaScript instanceof Array | Example code - EyeHunts
Apr 29, 2022 · JavaScript instanceof Array. Simple example code ways to detect an array instance in JavaScript. Array.isArray(value) The isArray() utility function returns true if value is an array. <!DOCTYPE html> <html> <body> <script> const array = [1, 2, 3]; console.log(Array.isArray(array)) </script> </body> </html> Output:
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