@rbxts/jsnatives

Array.isArray

Determines whether the passed value is an Array.

Signature

function isArray(array: unknown): array is unknown[]

Description

The Array.isArray() method determines whether the passed value is an Array. It returns true if the value is an Array, and false otherwise.

This method is particularly useful when you need to check if a value is an array before performing array-specific operations on it.

Examples

Basic usage

const array = [1, 2, 3];
const object = { a: 1, b: 2 };
const string = "hello";

print(ArrayUtils.isArray(array)); // true
print(ArrayUtils.isArray(object)); // false
print(ArrayUtils.isArray(string)); // false

Type narrowing

function processValue(value: unknown) {
  if (ArrayUtils.isArray(value)) {
    // In this block, value is typed as unknown[]
    return value.length;
  } else {
    // In this block, value is still unknown
    return 0;
  }
}

print(processValue([1, 2, 3])); // 3
print(processValue("not an array")); // 0

Working with proxy objects

const proxiedArray = new Proxy([1, 2, 3], {});
const proxiedObject = new Proxy({}, {});

print(ArrayUtils.isArray(proxiedArray)); // true
print(ArrayUtils.isArray(proxiedObject)); // false