Just something better then typeof
npm i easytypeconst type = require('easytype');
type() //'Undefined'
type(undefined) //'Undefined'
type(void 0) //'Undefined'
type(null) //'Null'
type('') //'String'
type('🦄') //'String'
type(true) //'Boolean'
type(false) //'Boolean'
type(type(Boolean()) //'Boolean'
type(type(Boolean(1)) //'Boolean'
type(type(new Boolean()) //'Boolean'
type(0) //'Number'
type(-1.5) //'Number'
type(NaN) //'Number'
type(Infinity) //'Number'
type(Number()) //'Number'
type(Number(-1.5)) //'Number'
type(Number('-1.5')) //'Number'
type(Number(true)) //'Number'
type(Number('1string')) //'Number'
type(Number('string')) //'Number'
type(new Number()) //'Number'
type(Symbol('test')) //'Symbol'
type(Symbol()) //'Symbol'
type({}) //'Object'
type(Object()) //'Object'
type(new Object()) //'Object'
type(Object.create(null)) //'Object'
type(Math) //'Math'
type(JSON) //'JSON'
type([]) //'Array'
type(Array()) //'Array'
type(new Array()) //'Array'
type(Array.from('123')) //'Array'
type(() => {}) //'Function'
type(function(){}) //'Function'
type(Object) //'Function'
type(new Function()) //'Function'
type(new Function('return 0;')) //'Function'
type(/^.*$/) //'RegExp'
type(new RegExp('^.*$')) //'RegExp'
type(new RegExp('ab+c', 'ig')) //'RegExp'
type(new Date()) //'Date'
type(new Date(0)) //'Date'
type(new Set()) //'Set'
type(new Map()) //'Map'
type(new WeakSet()) //'WeakSet'
type(new WeakMap()) //'WeakMap'
type(new Error()) //'Error'
type(new EvalError()) //'Error'
type(new RangeError()) //'Error'
type(new ReferenceError()) //'Error'
type(new SyntaxError()) //'Error'
type(new TypeError()) //'Error'
type(new URIError()) //'Error'
type(new Int8Array()) //'Int8Array'
type(new Uint8Array()) //'Uint8Array'
type(new Uint8ClampedArray()) //'Uint8ClampedArray'
type(new Int16Array()) //'Int16Array'
type(new Uint16Array()) //'Uint16Array'
type(new Int32Array()) //'Int32Array'
type(new Uint32Array()) //'Uint32Array'
type(new Float32Array()) //'Float32Array'
type(new Float64Array()) //'Float64Array'
type(new Promise(() => {})) //'Promise'
type((Promise.resolve(1)) //'Promise'
// Shortcuts: //
// returns true:
type.isUndefined()
type.isDefined('test')
type.isNull(null)
type.isString('')
type.isBoolean(true)
type.isNumber(1)
type.isArray([])
type.isObject({})
type.isFunction(() => {})
type.isRegExp(/^.*$/)
type.isDate(new Date())
type.isSet(new Set())
type.isMap(new Map())
type.isWeakSet(new WeakSet())
type.isWeakMap(new WeakMap())
type.isSymbol(Symbol('test'))
type.isError(new Error())
type.isPromise(new Promise(() => {}))
// returns false:
type.isUndefined('test')
type.isDefined()
type.isNull('null')
type.isString(true)
type.isBoolean('true')
type.isNumber('1')
type.isArray({length: 1})
type.isObject(null)
type.isFunction(global)
type.isRegExp('/^.*$/')
type.isDate('Sat Dec 23 2017 18:44:45 GMT+0300 (MSK)')
type.isSet(new WeakSet())
type.isMap(new WeakMap())
type.isWeakSet(new Set())
type.isWeakMap(new Map())
type.isSymbol([Symbol('test')])
type.isError(Error)
type.isPromise(Promise.all)
// Advanced:
type.isNumber.finite(0) //true
type.isNumber.finite(2e64) //true
type.isNumber.finite(-1.5) //true
type.isNumber.finite(NaN) //false
type.isNumber.finite(Infinity) //false
type.isNumber.finite(-Infinity) //false
type.isNaN(NaN) //true
type.isNaN('NaN') //false
type.isNaN(Infinity) //false
type.isNaN() //false
type.isNaN(0) //false
type.isNaN(null) //false
type.isNaN([NaN]) //false
// let's play with it:
const o = Object.create(null)
function F(){}
// pure object (null prototype)
type.isObject.pure(o) //true
type.isObject.pure({}) //false
type.isObject.pure(Object()) //false
type.isObject.pure(new Object()) //false
type.isObject.pure(new F()) //false
// plain object (native Object prototype)
type.isObject.plain({}) //true
type.isObject.plain(o) //true
type.isObject.plain(Object()) //true
type.isObject.plain(new Object()) //true
type.isObject.plain(Object(1)) //false
type.isObject.plain(new Object('')) //false
type.isObject.plain(new F()) //false
type.isObject.plain(new Date()) //false
type.isObject.plain([]) //false
type.isObject.plain(1) //false
type.isObject.plain(null) //false
type.isObject.plain() //false
// primitive (x !== Object(x))
type.isPrimitive(undefined) //true
type.isPrimitive(null) //true
type.isPrimitive(true) //true
type.isPrimitive(1) //true
type.isPrimitive('test') //true
type.isPrimitive(Boolean()) //true
type.isPrimitive(Number()) //true
type.isPrimitive(String()) //true
type.isPrimitive({}) //false
type.isPrimitive([]) //false
type.isPrimitive(Object(undefined)) //false
type.isPrimitive(Object(null)) //false
type.isPrimitive(Object(true)) //false
type.isPrimitive(Object(1)) //false
type.isPrimitive(Object('test')) //false
type.isPrimitive(new Boolean()) //false
type.isPrimitive(new Number()) //false
type.isPrimitive(new String()) //false
type.isPrimitive(new Date()) //false
type.isPrimitive(new F()) //false
// easy ('Boolean', 'Null', 'Number' or 'String')
type.isEasy(null) //true
type.isEasy(true) //true
type.isEasy(false) //true
type.isEasy(1) //true
type.isEasy('') //true
type.isEasy('test') //true
type.isEasy({}) //false
type.isEasy(Object()) //false
type.isEasy([]) //false
type.isEasy(new F()) //false
type.isEasy(undefined) //false
type.isEasy() //false
type.isEasy(Symbol('test')) //false
type.isArray.ofNumbers([0, -1.5, NaN]) //true
type.isArray.ofStrings(['', 'test']) //true
type.isArray.ofBooleans([true, false]) //true
type.isArray.ofFunctions([function(){}, () => {}, F]) //true
type.isArray.ofObjects([{}, Object(), new Object(), o]) //true
type.isArray.ofArrays([[], [1, 2, 3], Array(10)]) //true
type.isArray.ofPrimitives([undefined, null, true, 1, '']) //true
type.isArray.ofEasies([null, true, 1, '']) //true
type.isArray.empty([]) //true
// easy or array of easies
type.isSerializable(null) //true
type.isSerializable(true) //true
type.isSerializable(1) //true
type.isSerializable('') //true
type.isSerializable([]) //true
type.isSerializable([null, true, 1, '']) //true
type.isSerializable([undefined, [], {}]) //falseMIT