js :: getClassName :: type of object (ECMAScript standard to find the class of Object)

gistfile1.js

// ECMAScript standard to find the class of Object => Use toString method.

function getClassName(o) { return Object.prototype.toString.call(o).split(' ')[1].slice(0, -1) }
// OR
function getClassName(o) { return Object.prototype.toString.call(o).match(/^\[object\s(.*)\]$/)[1] }



console.log(getClassName([]));              // 'Array'
console.log(getClassName({}));              // 'Object'
console.log(getClassName(''));              // 'String'
console.log(getClassName(0));               // 'Number'
console.log(getClassName(NaN));             // 'Number'
console.log(getClassName(Infinity));        // 'Number'
console.log(getClassName(false));           // 'Boolean'
console.log(getClassName(null));            // 'Null'
console.log(getClassName(undefined));       // 'Undefined'
console.log(getClassName());                // 'Undefined'
console.log(getClassName(new Date()));      // 'Date'
console.log(getClassName(/r/));             // 'RegExp'
console.log(getClassName(function () {}));  // 'Function'
console.log(getClassName(new Error()));     // 'Error'


// Most of the logic is taken from
// http://perfectionkills.com/instanceof-considered-harmful-or-how-to-write-a-robust-isarray/
// http://www.adobe.com/devnet/html5/articles/object-types-in-javascript.html