/**
 * 
 * @desc   数据类型判断
 * @param  {Object} o
 * @param  {Object} obj
 * @return {Boolean}
 */
function dataType(o, type) {
    if (type) {
        var _type = type.toLowerCase();
    };
    switch (_type) {
        case 'string':
            return Object.prototype.toString.call(o) === '[object String]';
        case 'number':
            return Object.prototype.toString.call(o) === '[object Number]';
        case 'boolean':
            return Object.prototype.toString.call(o) === '[object Boolean]';
        case 'undefined':
            return Object.prototype.toString.call(o) === '[object Undefined]';
        case 'null':
            return Object.prototype.toString.call(o) === '[object Null]';
        case 'function':
            return Object.prototype.toString.call(o) === '[object Function]';
        case 'array':
            return Object.prototype.toString.call(o) === '[object Array]';
        case 'object':
            return Object.prototype.toString.call(o) === '[object Object]';
        case 'nan':
            return isNaN(o);
        case 'elements':
            return Object.prototype.toString.call(o).indexOf('HTML') !== -1;
        default:
            return Object.prototype.toString.call(o);
    };
};

module.exports = dataType;