@nick/is/array-like-object

isArrayLikeObject

Signature

function isArrayLikeObject<T>(it: unknown): it is ArrayLikeObject<T>;

Checks if a given value is an ArrayLike object. This is a stricter form of the isArrayLike check that only returns true if a value is an object that also meets all of the ArrayLike conditions:

• it is not a function
• it has an own property named length that is a finite unsigned integer:
  • an integer between 0 and Number.MAX_SAFE_INTEGER
  • it is non-negative, NaN, Infinity, nor -Infinity

Parameters

Name	Info
it	The value to check.

Returns

true if the value is an object that meets all of the ArrayLike conditions, otherwise false.

Category

Indexed Collections

See Also

• isArrayLike for a version that allows for non-object values such as strings (but not functions).

Examples

import { isArrayLikeObject } from "jsr:@nick/is/array-like";

isArrayLikeObject([]); // true
isArrayLikeObject({ length: 0 }); // true
isArrayLikeObject({ length: 1, 0: "a" }); // true

// strings are not considered ArrayLike objects
isArrayLikeObject("abc"); // false

// length must be a finite unsigned integer
isArrayLikeObject({ length: Infinity }); // false

// length must be non-negative
isArrayLikeObject({ length: -1 }); // false

// length cannot be a non-number or NaN
isArrayLikeObject({ length: "a" }); // false
isArrayLikeObject({ length: NaN }); // false

// functions are not considered ArrayLike objects, despite meeting the
// requirements for the 'length' property. this is because they are not
// indexed collections like an array or string.
isArrayLikeObject(() => {});

ArrayLikeObject

Signature

export type ArrayLikeObject<T = unknown> = ArrayLike<T> & object;

Represents an object that has a length property that is a finite unsigned integer, and where the object is not a function. This is the type that the function isArrayLikeObject narrows its inputs to.

Type Parameters

• T (default: unknown)

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Category

Indexed Collections