JS Practice — Built-in Objects

Array.isArray() — basic check

📖 Usage Example

Array.isArray([1, 2, 3])   // → true
Array.isArray('hello')     // → false
Array.isArray({length: 3}) // → false

Use Array.isArray() to reliably check whether a value is an array.

Array.isArray()

Array.isArray(value) returns true if and only if the value is an Array object. It is the most reliable way to check for arrays — more reliable than instanceof Array when working across iframes or with subclasses.

Challenge: Implement isItAnArray that returns true when the value is an array and false otherwise.

isItAnArray([1, 2, 3]) // → true
isItAnArray('hello')   // → false
isItAnArray({})        // → false

💡 Hints (2)

• `Array.isArray` is the canonical, spec-defined way to test for arrays.
• It correctly returns `false` for `null`, `undefined`, objects, and strings.