Check if the object passed exists - JavaScript - Is not null, not undefined and not empty

checkObjExists.js

exists = function(obj) {
		if (typeof obj !== 'undefined') {
			if (obj !== null && obj !== undefined) {
				if (typeof obj === 'string') {
					return obj !== '';
				} else if (typeof obj === 'number') {
					return obj !== 0;
				} else {
					/* Node.js supports JSON.stringify(obj) syntax.
					 * For other versions of JS, this should be replaced with appropriate syntax.
					 */
					return JSON.stringify(obj) !== '{}';
				}
			}
		}
		return false;
	};