Underscore.JS isUndefined方法

_.isUndefined(object)

var _ = require('underscore');

var value;
//Example 1: Check if argument passed is undefined
console.log(_.isUndefined(value));

value = 0;
//Example 2: Check if argument passed is not undefined
console.log(_.isUndefined(value));

>node tester.js

true
false