no-instanceof-array.md

Require Array.isArray() instead of instanceof Array

✅ This rule is part of the recommended config.

🔧 This rule is auto-fixable.

The instanceof Array check doesn't work across realms/contexts, for example, frames/windows in browsers or the vm module in Node.js.

Fail

array instanceof Array;
[1,2,3] instanceof Array;

Pass

Array.isArray(array);
Array.isArray([1,2,3]);