get proper type of any value

type.js

var toString = Object.prototype.toString,
    regexp = /\[object (.*?)\]/;

function type(o) {
    var match = toString.call(o).match(regexp);

    return match[1].toLowerCase();
}

type.single.line.coffee

type = (o) -> Object::toString.call(o).match(/\[object (.*?)\]/)[1].toLowerCase()

type.single.line.js

function type(o) {return Object.prototype.toString.call(o).match(/\[object (.*?)\]/)[1].toLowerCase();}

type.test.spec.coffee

describe '::type', ->
  it 'should always return string', ->
    expect(type()).toBeString()
    expect(type(10)).toBeString()
  
  it 'should work as "typeof" for basic types', ->
    expect(type(1)).toBe 'number'
    expect(type(1.1)).toBe 'number'
    expect(type(false)).toBe 'boolean'
    expect(type('')).toBe 'string'
    expect(type({})).toBe 'object'
    expect(type(->)).toBe 'function'
  
  it 'should return "array" for []', ->
    expect(type([])).toBe 'array'
  
  it 'should return "nan" for NaN', ->
    expect(type(NaN)).toBe 'nan'
  
  it 'should return "regexp" for RegExp', ->
    expect(type(/a/)).toBe 'regexp'
  
  it 'should work with constructors', ->
    expect(type(new Number(1))).toBe 'number'
    expect(type(new Number(1.1))).toBe 'number'
    expect(type(new Boolean(false))).toBe 'boolean'
    expect(type(new String(''))).toBe 'string'
    expect(type(new Object())).toBe 'object'
    expect(type(new Function())).toBe 'function'