6. Code inside snippets

You can write whatever JavaScript code you like inside your snippets. The iffinity engine uses the EJS template system. You don't need to worry much about it, though. The following cases will cover you 99% of the time.

Arbitrary JavaScript

You can write any JavaScript you want inside <% ... %> EJS tags. Note that each such section is scoped, meaning that no variables or other stuff will leak from it. The code will run as soon as the snippet is shown (every time). Example:

<snippet name="A Snippet">
    ...
    <%
        alert('Hello world!') // an alert will pop up every time this snippet is shown
    %>
    ....
</snippet>

Important note: Always remember to use $(function () { ... }); provided by jQuery (which is available in every EJS code segment by iffinity) whenever you want to access DOM elements from your code. Example:

<snippet name="A Snippet">
    <h1>Chapter 1</h1>
    <%
        $(function () {
            // create a fade in effect for the snippet title
            $("h1").hide().fadeIn(1000);
        });
    %>
    ....
</snippet>

Value interpolation

You can interpolate JavaScript values using the <%= ... %> EJS tags (same as before, plus a =). Example:

<snippet name="A Snippet">
    <% if (s.TIMES_DIED === undefined) s.TIMES_DIED = 0 %>
    <p>You have died <%= s.TIMES_DIED %> times.</p>
    ....
</snippet>

Exposed variables inside EJS snippets

Every code you write inside EJS tags has access to the following variables created by iffinity:

• story: The story object
• snippet: The current snippet object
• s: The story state object (shorthand for the story.state field)
• f: The story functions object (shorthand for the story.funcs field)

Note that the only way to have variables/computations etc escape a certain EJS segment and live on is to store them in the story state s. For functions, the pseudo-variable f is recommended (shorthand for the story.funcs field). The only difference between s and f is that s is serialized by the save() method of the Story object, so functions won't survive this. For more information, see the page on the author API.