Wots NPM | npm.io

why?

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

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()