underscore.js _.isNumber[Object]

Returns true if object is a Number (including NaN).

返回true，如果是数字类型,包括NAN

  _.isNumber = function(obj) {
    return toString.call(obj) == '[object Number]';
  };

源码:

 _.isNumber = function(obj) {
    return toString.call(obj) == '[object Number]';
  };