在EJS github页面上,只有一个简单的例子:https: //github.com/visionmedia/ejs
例
<% if (user) { %>
<h2><%= user.name %></h2>
<% } %>
这似乎是检查是否存在名为user的变量,如果存在,则执行一些操作.呃,对吗？
我的问题是,如果用户变量不存在,为什么Node会抛出一个ReferenceError？这使得上面的例子变得毫无用处.检查变量是否存在的合适方法是什么？我是否希望使用try/catch机制并获取ReferenceError？
ReferenceError: user is not defined
at IncomingMessage.anonymous (eval at <anonymous> (/usr/local/lib/node/.npm/ejs/0.3.1/package/lib/ejs.js:140:12))
at IncomingMessage.<anonymous> (/usr/local/lib/node/.npm/ejs/0.3.1/package/lib/ejs.js:142:15)
at Object.render (/usr/local/lib/node/.npm/ejs/0.3.1/package/lib/ejs.js:177:13)
at ServerResponse.render (/usr/local/lib/node/.npm/express/1.0.7/package/lib/express/view.js:334:22)
at Object.<anonymous> (/Users/me/Dropbox/Projects/myproject/server.js:188:9)
at param (/usr/local/lib/node/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:146:21)
at pass (/usr/local/lib/node/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:162:10)
at /usr/local/lib/node/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:152:27
at Object.restrict (/Users/me/Dropbox/Projects/myproject/server.js:94:5)
at param (/usr/local/lib/node/.npm/connect/0.5.10/package/lib/connect/middleware/router.js:146:21)
我明白我可以通过在我的服务器代码中添加一个"用户"局部变量来消除这个错误,但这里的重点是我想在运行时使用你的每天if/else来检查这些变量是否存在nullcheck类型模式.不存在的变量的例外对我来说似乎很荒谬.