`@untydev/types`

Dynamic type checking utilities for JavaScript.

Introduction

The @untydev/types package provides various functions for checking and ensuring dynamic types of JavaScript values.

Installation

Using NPM:

``

shell

npm i @untydev/types





Usage

js

import { ensureArray, ensureFunction } from '@untydev/types'



function map (arr, fn) {

  ensureArray(arr)

  ensureFunction(fn)  

  return arr.map(fn)

}





API



$3



Checks whether

v is null

js

import { isNull } from '@untydev/types'



isNull(null) === true





$3



Checks whether

v is undefined

js

import { isUndefined } from '@untydev/types'



isUndefined() === true

isUndefined(undefined) === true





$3



Checks whether

v is either true or false

js

import { isBoolean } from '@untydev/types'



isBoolean(true) === true

isBoolean(false) === true





$3



Checks whether

v is an integer using Number.isSafeInteger

js

import { isInteger } from '@untydev/types'



isInteger(1) === true

isInteger(0.1) === false

isInteger(NaN) === false

isInteger(Infinity) === false





$3



Checks whether

 is a number, excluding infinite values.

js

import { isNumber } from '@untydev/types'



isNumber(1) === true

isNumber(NaN) === false

isNumber(Infinity) === false





$3



Checks whether

v is a BigInt

js

import { isBigInt } from '@untydev/types'



isBigInt(1) === false

isBigInt(1n) === true

isBigInt(BigInt(1)) === true





$3



Checks whether

v is a string, excluding String

 object.

js

import { isString } from '@untydev/types'



isString('') === true





$3



Checks whether

v is an array using Array.isArray

js

import { isArray } from '@untydev/types'



isArray([]) === true





$3



Checks whether

 is a function.

js

import { isFunction } from '@untydev/types'



isFunction(() => null) === true





$3



Checks whether

 is a non-null object or a function.

js

import { isObject } from '@untydev/types'



isObject({}) === true

isObject([]) === true

isObject(() => null) === true

isObject(null) === false

isObject('') === false





$3



Checks whether

v is an object a plain object which is an object created by the Object

 constructor or one with a

[[Prototype]] of null.

``

js

import { isPlainObject } from '@untydev/types'



isPlainObject({}) === true

isPlainObject(Object.create(null)) === true

isPlainObject(null) === false



class X {}

isPlainObject(new X()) === false





$3



Checks whether

v is a Symbol

js

import { isSymbol } from '@untydev/types'



isSymbol(Symbol('test')) === true





$3



Checks whether

 is iterable, e.g. implements the iterable protocol

js

import { isIterable } from '@untydev/types'



isIterable('') === true

isIterable([]) === true

isIterable({}) === false





$3



Checks whether

v is promise-like, e.g. implements then

 method.

js

import { isPromise } from '@untydev/types'



isPromise(Promise.resolve()) === true

isPromise({ then: () => null }) === true





$3



Additionally, every

is function has a ensure counterpart, which throw TypeError exceptions if v

 is not a correct type.

js

import { ensureIterable } from '@untydev/types'



ensureIterable(null) // throws TypeError('Expected iterable but got null')





$3



Similarly to

typeof operator, returns the type of v

. It handles several special cases:

js

import { typeOf } from '@untydev/types'



typeOf(null) === 'null'

typeOf(NaN) === 'NaN'

typeOf(Infinity) === 'infinity'