A very simple "typeof" detection


Keywords
isArray, isDate, isNaN, isInfinity, isNull, isUndefined, isObject, isRegExp, isString, kind, type, typeof
License
ISC
Install
npm install wots@0.3.2

Documentation

why?

The library was written as a simple coding exercise, but then appeared useful to share 😉

how?

npm install --save wots

and then

// use as ES6 module
import wots from 'wots';

// use in NodeJs
var wots = require('wots');

// use as global variable via UnPKG
<script src="https://unpkg.com/wots"></script>

// ... then ...

if (wots(myNotAlwaysNumericVariable) === 'NaN') {
  // do some stuff
  // e.g. console.log('I cannot count on it')
} else if (wots(myNotAlwaysNumericVariable) === 'Infinity') {
  // do some other stuff
  // e.g. console.log('Please do not force me to use this value in a loop!')
}

what?

wots() function returns reasonable type names for tested values:

description input result
null null 'null'
undefined undefined 'undefined'
strings 'foo' 'string'
'' 'string'
['Hello', 'world!'].join(' ') 'string'
new String() 'string'
numbers 5 'number'
parseInt(42) 'number'
new Number('3') 'number'
NaN 'NaN'
Infinity 'Infinity'
1 / -0 'Infinity'
boolean values false 'boolean'
!!nonEmptyVariable 'boolean'
new Boolean('0') 'boolean'
regular expressions /^test$/g 'regexp'
new RegExp('needle', 'i') 'regexp'
arrays ['foo', 'bar', 'baz'] 'array'
new Array(10) 'array'
objects { foo: 'bar'} 'object'
{} 'object'
new Object() 'object'
Object.create(null) 'object
functions function () {} 'function'
new Function('return null') 'function'
date objects new Date() 'date'
errors new Error('error!') 'error'
new TypeError('type error!') 'error'
arguments objects (function(){return arguments;})() 'arguments'
class constructors new MyClass() 'myclass'
new Buffer() 'buffer'
new XMLHttpRequest() 'xmlhttprequest'
promises new Promise(function() {}) 'promise'
Promise.resolve('data') 'promise'
Promise.reject(new Error('Oop!')) 'promise'

Note: for more examples see test file

Since version 0.2.0 the library also exposes static methods listed below:

wots.isNull()
wots.isUndefined()
wots.isString()
wots.isNumber()
wots.isNaN()
wots.isInfinity()
wots.isBoolean()
wots.isRegExp()
wots.isArray()
wots.isObject()
wots.isFunction()
wots.isDate()
wots.isError()
wots.isArguments()
wots.isPromise()

the name

wots basically stands for what is but is shorter 😉