isEmptyArray.md

isEmptyArray

A type-validation that checks if a value is an empty array.

Parameters

value

Value to validate

Type: unknown

rejectionReasons

Optional callback that would be called with validation rejection reasons.

• When validation succeeds - rejectionReasons would not be invoked.
• When validation fails - rejectionReasons would be invoked at least once and may be invoked multiple times.

Properties

Symbol: [typeValidatorType]

A description of the validated type

Type: string

Methods

asPredicate(): (value: unknown) => boolean

Returns a predicate (no second argument) for the specified validator.

asPredicate(): (value: unknown) => value is []

Returns a type-guard predicate (no second argument) for the specified validator.

Example

import { isEmptyArray, typeValidatorType } from '@altostra/type-validations'

console.log(isEmptyArray[typeValidatorType]) // []

console.log(isEmptyArray([], console.log)) // true

console.log(isEmptyArray('A', console.log)) /* { path: [], reason: "Value <'A'> is not an array", propertyType: '[]' }
false */
console.log(isEmptyArray([0], console.log)) /* { path: [], reason: 'Array <[ 0 ]> is not empty', propertyType: '[]' }
false */

const incognito: unknown = []

if (isEmptyArray(incognito)) {
    console.log(incognito.length) // 0

    // @ts-expect-error: This condition will always return 'false' since 
    // the types '0' and '1' have no overlap.
    console.log(incognito.length === 1) // false
}