<p>一个Node.js项目由三个文件组成:app1.js、app2.js和app3.js。每个文件的代码片段如下。如果我们执行app2.js,会得到什么输出?( )<br/> [app1.js:]<br/> module.exports = {value1: "Hello"}<br/> /******************************************/<br/> [app2.js:]<br/> var app1 = require("./app1");<br/> console.log("Initial value:", app1.value1);<br/> app1.value1 = "World';<br/> var app3 = require("./app3");<br/> /******************************************/<br/> [app3.js:]<br/> var app3 = require("./app2");<br/> console.log("Final value:", app3.value1);</p>
<p> <br/> Initial value: Hello<br/> Final value: Hello </p>
<p> <br/> Initial value: Hello<br/> Final value: World </p>
<p> <br/> Initial value: Hello<br/> Final value: undefined </p>
<p> <br/> Initial value: Hello</p>
<p> <br/> 由于程序出错,不会显示任何输出。</p>