node-asyncEJS implements a templating language for embedding JavaScript into other text documents such as HTML. It adds new features to the classic ERB syntax to enable asynchronous execution of the template.

When to use

You can always use the synchronous features. So use it whenever you need a templating solution.

The asynchronous features come in handy when you

want to flush the output to the client as early as possible
need to stream your generated content

Usage

Template

<html>
  <head>
    <% ctx.hello = "World";  %>
    <title><%= "Hello " + ctx.hello %></title>
  </head>
  <body>

    <h1><%? setTimeout(function () { res.print("Async Header"); res.finish(); }, 2000)  %></h1>
    <p><%? setTimeout(function () { res.print("Body"); res.finish(); }, 1000)  %></p>

  </body>
</html>

JavaScript

var te = require("../lib/asyncEJS").Engine();

te.template("template.t.html", function () {

  var templateResponse = template(paras);

  templateResponse.addListener("body", function (chunk) {
    sys.print(chunk);
  });

  templateResponse.addListener("complete", function () {
    sys.puts("COMPLETE")
  });
});

Templates

Special Variables

ctx contains the parameter that was passed to the template function

res represents the output of the template.

res.print("string") prints more output into the template

res.finish() tells the template that the current asynchronous blocks has finished execution

Basic Template Commands

<% var javascript = "code" %> executes arbitrary JavaScript

<%= "Hello " + ctx.hello %> outputs the statement result into the template

Asynchronous Templates

<%? setTimeout(function () { res.print("Async Header"); res.finish(); }, 2000)  %>

<%? introduces a block that will be expected to execute asynchronously with respect to the rest of the template. The rest of the template will continue executing but no output will be returned until the res.finish() method will be called.

Partials

<% res.partial("partial.js.html", { hello: "world" }); %>

`res.partial(filename, paras)

Escaping

There is currently no escaping of output but this will change.

JavaScript Usage

Template Engine

Construct a template engine with

var te = require("../lib/asyncEJS").Engine({
  autoUpdate: false,
  templateRoot: '/path/to/templates'
});

If autoUpdate is true, asyncEJS will continously look for changes in templates and automatically update them when they change on disk.

templateRoot is a directory where templates will be served from. If omitted, templates will be served from the current working directory.

Loading Templates

After you instantiated a template engine use the template method to create a template function.

te.template("template.t.html", function (template) { ... });

Executing the template function with paras will return a templateResponse. The paras are accessible as ctx variable inside the template.

var templateResponse = template(paras);

Template Responses

The template response emits two events body and complete

templateResponse.addListener("body", function (chunk) {
  sys.print(chunk);
});

templateResponse.addListener("complete", function () {
  sys.puts("COMPLETE")
});

body is emitted whenever a part of the template has been completed.

complete will fire once when the template has fully executed.

Examples

See examples/ and test/

FAQs

What is asyncEJS?

Is asyncEJS popular?

Is asyncEJS well maintained?

Package last updated on 15 Jun 2011

Did you know?

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.

Install

asyncEJS

node-syncEJS - 0.0.1