no-instanceof-array.md

Pattern: instanceof Array check

Issue: -

Description

Using instanceof Array to check for arrays doesn't work reliably across different contexts (e.g., frames/windows in browsers or VM modules in Node.js). Use Array.isArray() instead.

Examples

Example of incorrect code:

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

Example of correct code:

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