(Better) JavaScript Type Detection

(Better) JavaScript Type Detection

/* Better type detection */
/*
- Checking a supposed array for a method like slice() isn't robust enough, as there's no reason why a non-array couldn't have a method of the same name 
- instanceof Array works incorrectly when used across frames in some IE versions
*/
// ARRAY
var alpha = [];
console.log( typeof alpha ); // "object"
console.log( alpha.constructor === Array ); // true
console.log( Object.prototype.toString.call( alpha ) ); // "[object Array]"
console.log( Array.isArray( alpha ) ); // true (ECMAScript 5 only)

// OBJECT
var bravo = {};
console.log( bravo.constructor === Object ); // true
console.log( Object.prototype.toString.call( bravo ) ); // "[object Object]"

// STRING
var charlie = "Hello";
console.log( charlie.constructor === String ); // true
console.log( Object.prototype.toString.call( charlie ) ); // "[object String]"

// NUMBER
var delta = 1;
console.log( delta.constructor === Number ); // true
console.log( Object.prototype.toString.call( delta ) ); // "[object Number]"

// BOOLEAN
var echo = false;
console.log( echo.constructor === Boolean ); // true
console.log( Object.prototype.toString.call( echo ) ); // "[object Boolean]"

// REGULAR EXPRESSION
var foxtrot = /foo/gmi;
console.log( foxtrot.constructor === RegExp ); // true
console.log( Object.prototype.toString.call( foxtrot ) ); // "[object RegExp]"

// NULL
var golf = null;
console.log( golf.constructor ); // Cannot read property 'constructor' of undefined
console.log( Object.prototype.toString.call( golf ) ); // "[object Null]"

// UNDEFINED
var hotel;
console.log( hotel.constructor ); // Cannot read property 'constructor' of undefined
console.log( Object.prototype.toString.call( hotel ) ); // "[object Undefined]"