如果条件不起作用，则EJS

Question

I am currently trying to use ejs template in my express application. As indicated in the offical page of the template ( https://www.npmjs.com/package/ejs ) I am using if conditional to output variable if it has been defined . Like this

  <% if (msg) { %>
  <h2><%=msg %></h2>
  <% } else {%>
  <h2>There is no messages</h2>
  <% } %>

Unfortunately, everytime I do this server returns 500 error . How do I resolve this?

Answer 1

You can't use if (msg) - that's the bit that errors.

Instead, check for existence some other way - by using typeof for instance:

<% if (typeof msg != "undefined") { %>
<h2><%=msg %></h2>
<% } else {%>
<h2>There is no messages</h2>
<% } %>'