Package Exports

handy-types
handy-types/dist/index.js

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Readme

Handy-Types

A small library to check variable types. It consists of many utility functions like int, positive_int, array, non_empty_array and many more. Every type(function) has their full name in case you want to write a meaningful error message. The library is fully tested so it has 100% test coverage. It uses the UMD module system so it supports every JavaScript environment that uses any kind JavaScript of module system.

Example

const { types, typeNames } = require("handy-types");
// Or: import { types, typeNames } from "handy-types";

const user = {};

if(!types.ne_object(obj)) // or use the long form: types.non_empty_object(obj)
  throw new Error(`"user" must be of type "${typeNames.ne_object}"`);

All the available types are listed below.

Note: I didn't follow strict mathematical definition for positive and negative numbers. From mathematical perspective all the "positive_<type>" used here should be called "non_negative_<type>". So be sure to check all the types before using them.

Number Types

Type	Full Name	Alias	Implementation
number	Number	num	`typeof n === "number" && !Number.isNaN(n)`
finite_num	Finite Number		`Number.isFinite(n)`
positive_number	Positive Number	p_number	`n >= 0`
strict_positive_number	Strict Positive Number	sp_number	`n > 0`
negative_number	Negative Number	n_number	`n < 0`
non_positive_number	Non Positive Number	np_number	`n <= 0`

Integer Types

Type	Full Name	Alias	Implementation
integer	Integer	int	`Number.isInteger(n)`
safe_int	Safe Integer		`Number.isSafeInteger(n)`
positive_int	Positive Integer	p_int	`integer >= 0`
strict_positive_int	Strict Positive Integer, Natural Number	natural_num, sp_int	`integer > 0`
negative_int	Negative Integer	n_int	`integer < 0`
non_positive_int	Non Positive Integer	np_int	`integer <= 0`
odd	Odd Number		`Math.abs(n % 2) === 1`
even	Even Number		`n % 2 === 0`

Note: For even and odd type you must pass an integer to them otherwise you may get wrong result in the following case.

const num = 4.32;

if(types.even(num)) {
  // num is even
} else {
  // But here num is not necessarily odd
}

So if we can make sure that num is an integer then we'll get predicted results.

const num = 4.32;

if(types.int(num)) {
  if(types.even(num)) {
    // num is even
  } else {
    // num is odd
  }
}

// Or always check for both cases
if(types.even(num)) {
  // num is even
} else if(types.odd(num)) {
  // num is odd
}

Primitive Integer

Type	Full Name	Range
int8	8 Bit Integer	-128 to 127
uint8	8 Bit Unsigned Integer	0 to 255
int16	16 Bit Integer	-32,768 to 32,767
uint16	16 Bit Unsigned Integer	0 to 65,535
int32	32 Bit Integer	-2,147,483,648 to 2,147,483,647
uint32	32 Bit Unsigned Integer	0 to 4,294,967,295

String Types

Type	Full Name	Alias
string	String
empty_string	Empty String	es
non_empty_string	Non-Empty String	ne_string

Object Types

Type	Full Name	Alias
object	Object
empty_object	Empty Object	eo
non_null_object	Non-Null Object	nn_object
non_empty_object	Non-Empty Object	ne_object

Array Types

Type	Full Name	Alias
array	Array
empty_array	Empty Array	ea
non_empty_array	Non-Empty Array	ne_array

Global Objects

Type	Full Name	Alias
regex	Regular Expression
date	Date
set	Set
map	Map

Other Native Types

Type	Full Name	Alias
function	Function
symbol	Symbol

Boolean Type

Type	Full Name	Alias
boolean	Boolean
truthy	Truthy
falsy	Falsy

Constants

Type	Full Name	Alias
true	True
false	False
undefined	Undefined
null	Null
NaN	Not A Number

Other Types

Type	Full Name	Alias
defined	Defined
any	Any
nullish	Nullish

If you find a bug or want to add a new type feel free to make a pull request :)