Hiccups

Hiccups is a ClojureScript port of the Hiccup HTML generation library. It uses vectors to represent tags, and maps to represent a tag's attributes.

The goal is to provide similar performance to Closure Templates with a much more Clojure friendly syntax.

Differences from Hiccup

• In ClojureScript, macros need to be defined in separate Clojure namespaces. Because of this, core functionality is split into two files: core.clj contains the macros and compile-time only functions, and runtime.cljs contains functions that are also available at runtime. The contents of runtime.cljs are also used at compile-time, so the goal is to keep it portable between ClojureScript and Clojure.
• HTML is escaped by default, use :dangerously-set-inner-HTML to explicitly disable escaping.
• Unit tests are run in a PhantomJS browser using lein-cljsbuild and Closure's testing libs.
• Not everything has been ported yet. See ToDo.

Alternatives

• Crate is an alternative Hiccup style library for ClojureScript. The main difference between Crate and Hiccups is that Crate generates DOM nodes and Hiccups generates strings. There are a few reasons why you might consider Hiccups over Crate (YMMV, of course):
  • As with the original Hiccup, Hiccups tries to do as much as possible at compile time, with macro expansion.
  • Working with strings can be much more performant than working with DOM nodes, especially with large amounts of markup, and especially with older browsers.
  • Easier to use in headless environments like Node.js
• Closure Templates is Google's Closure templating library.

Install

Add the following dependency to your project.clj file:

Usage

Require both the core macros and the runtime functions in your namespace declaration:

(ns myns
  (:require-macros [hiccups.core :as hiccups :refer [html]])
  (:require [hiccups.runtime :as hiccups]))

(hiccups/defhtml my-template []
  [:div
    [:a {:href "https://github.com/weavejester/hiccup"}
      "Hiccup"]])

Syntax

Here is a basic example of Hiccups syntax:

(html [:span {:class "foo"} "bar"])
"<span class=\"foo\">bar</span>"

The first element of the vector is used as the tag name. The second attribute can optionally be a map, in which case it is used to supply the tag's attributes. Every other element is considered part of the tag's body.

Hiccups is intelligent enough to render different HTML tags in different ways, in order to accommodate browser quirks:

(html [:script])
"<script></script>"
(html [:p])
"<p />"

And provides a CSS-like shortcut for denoting id and class attributes:

(html [:div#foo.bar.baz "bang"])
"<div id=\"foo\" class=\"bar baz\">bang</div>"

If the body of the tag is a seq, its contents will be expanded out into the tag body. This makes working with forms like map and for more convenient:

(html [:ul
        (for [x (range 1 4)]
          [:li x])])
"<ul><li>1</li><li>2</li><li>3</li></ul>"

Note that while lists are considered to be seqs in Clojure(Script), vectors and sets are not. As a consequence, Hiccups will bail out if a vector is passed in without a tag: [[:div] [:div]].

Disabling HTML escaping is accomplished by using React inspired :dangerously-set-inner-HTML attribute:

[:div
 {:dangerously-set-inner-HTML
  {:__html "<p>safe html</p>"}}]

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See the Hiccup wiki for more information.

ToDo

• Catch up with recent changes in Hiccup.
• Form helpers
• Page helpers
• Figure out if the runtime can be pulled in without an explicit require by the user
• Explore potential performance improvements using Google's StringBuffer et al.