Class Guard

Staticfactory

StatichasProperty

• hasProperty<T extends PropertyName>(
      obj: unknown,
      key: T,
  ): obj is Record<T, unknown>

  Checks if an object has a given property key.

  Type Parameters

  • T extends PropertyName

  Parameters

  • obj: unknown

    The object to check.
  • key: T

    The property key to look for.

  Returns obj is Record<T, unknown>

  True if the object contains the property key.

StaticisArray

• isArray<T extends unknown>(value: unknown): value is T[]

  Checks if a value is an array.

  Type Parameters

  • T extends unknown

  Parameters

  • value: unknown

    The value to check.

  Returns value is T[]

  True if value is an array.

StaticisBoolean

• isBoolean(value: unknown): value is boolean

  Checks if a value is a boolean.

  Parameters

  • value: unknown

    The value to check.

  Returns value is boolean

  True if value is of type boolean.

StaticisEmptyArray

• isEmptyArray(value: unknown[]): value is []

  Checks if an array is empty.

  Parameters

  • value: unknown[]

    The array to check.

  Returns value is []

  True if the array has no elements.

StaticisEmptyString

• isEmptyString(value: string): value is ""

  Checks if a string is exactly the empty string ("").

  Parameters

  • value: string

    The string to check.

  Returns value is ""

  True if the string is empty.

StaticisLiteral

• isLiteral<T extends Literal>(
      value: unknown,
      ...literals: readonly T[],
  ): value is T

  Checks if a value equals one of the provided literal values.

  Type Parameters

  • T extends Literal

  Parameters

  • value: unknown

    The value to check.
  • ...literals: readonly T[]

    A list of literal values to compare against.

  Returns value is T

  True if value is included in the provided literals.

StaticisNotEmptyArray

• isNotEmptyArray<T>(value: T[]): value is T[]

  Checks if an array is not empty.

  Type Parameters

  • T

  Parameters

  • value: T[]

    The array to check.

  Returns value is T[]

  True if the array has at least one element.

StaticisNotEmptyString

• isNotEmptyString<T extends string>(value: T): value is T

  Checks if a string is not empty.

  Type Parameters

  • T extends string

  Parameters

  • value: T

    The string to check.

  Returns value is T

  True if the string is non-empty.

StaticisNotNullish

• isNotNullish<T>(value: Nullable<T>): value is T

  Checks if a value is not nullish.

  Type Parameters

  • T

  Parameters

  • value: Nullable<T>

    The value to check.

  Returns value is T

  True if value is not Nullish (null or undefined).

StaticisNullish

• isNullish(value: unknown): value is Nullish

  Checks if a value is nullish.

  Parameters

  • value: unknown

    The value to check.

  Returns value is Nullish

  True if value is Nullish (null or undefined).

StaticisNumber

• isNumber(value: unknown): value is number

  Checks if a value is a number.

  Parameters

  • value: unknown

    The value to check.

  Returns value is number

  True if value is a number.

StaticisObject

• isObject(value: unknown): value is Record<PropertyName, unknown>

  Checks if a value is an object (excluding arrays and Nullable).

  Parameters

  • value: unknown

    The value to check.

  Returns value is Record<PropertyName, unknown>

  True if value is an object, false otherwise.

StaticisPlainObject

• isPlainObject(value: unknown): value is Record<PropertyName, unknown>

  Checks if a value is a "plain" object, meaning it was created by the object constructor or with an object literal ({}).

  This guard is stricter than isObject because it excludes instances of custom classes, which isObject would otherwise identify as objects.

  Parameters

  • value: unknown

    The value to check.

  Returns value is Record<PropertyName, unknown>

  True if value is a plain object, false otherwise.

StaticisSpecificValue

• isSpecificValue<T>(value: unknown, expected: T): value is T

  Checks if a value is strictly equal to a specific expected value.

  Type Parameters

  • T

  Parameters

  • value: unknown

    The value to check.
  • expected: T

    The specific value to compare against.

  Returns value is T

  True if value equals expected.

StaticisString

• isString(value: unknown): value is string

  Checks if a value is a string.

  Parameters

  • value: unknown

    The value to check.

  Returns value is string

  True if value is a string.

StaticisTuple

• isTuple<T extends unknown[]>(
      value: unknown,
      ...guards: GuardFuncCollection<T>,
  ): value is T

  Checks if a value is a tuple with the exact length and types, verified using the provided guard functions for each position.

  Type Parameters

  • T extends unknown[]

  Parameters

  • value: unknown

    The value to check.
  • ...guards: GuardFuncCollection<T>

    A guard function for each element in the tuple.

  Returns value is T

  True if value is a tuple matching the guard pattern.