/*
---------------------- JavaScript Micro-Templating ----------------------
I?ve had a little utility that I?ve been kicking around for some time now that I?ve found to be quite useful in my JavaScript application-building endeavors. It?s a super-simple templating function that is fast, caches quickly, and is easy to use. I have a couple tricks that I use to make it real fun to mess with.
Here?s the source code to the templating function (a more-refined version of this code will be in my upcoming book Secrets of the JavaScript Ninja):
*/
// Simple JavaScript Templating
// John Resig - http://ejohn.org/ - MIT Licensed
(function(){
var cache = {};
this.tmpl = function tmpl(str, data){
// Figure out if we're getting a template, or if we need to
// load the template - and be sure to cache the result.
var fn = !/\W/.test(str) ?
cache[str] = cache[str] ||
tmpl(document.getElementById(str).innerHTML) :
// Generate a reusable function that will serve as a template
// generator (and which will be cached).
new Function("obj",
"var p=[],print=function(){p.push.apply(p,arguments);};" +
// Introduce the data as local variables using with(){}
"with(obj){p.push('" +
// Convert the template into pure JavaScript
str
.replace(/[\r\t\n]/g, " ")
.split("<%").join("\t")
.replace(/((^|%>)[^\t]*)'/g, "$1\r")
.replace(/\t=(.*?)%>/g, "',$1,'")
.split("\t").join("');")
.split("%>").join("p.push('")
.split("\r").join("\\'")
+ "');}return p.join('');");
// Provide some basic currying to the user
return data ? fn( data ) : fn;
};
})();
/*
You would use it against templates written like this (it doesn?t have to be in this particular manner ? but it?s a style that I enjoy):
*/
/* <script type="text/html" id="item_tmpl">
<div id="<%=id%>" class="<%=(i % 2 == 1 ? " even" : "")%>">
<div class="grid_1 alpha right">
<img class="righted" src="<%=profile_image_url%>"/>
</div>
<div class="grid_6 omega contents">
<p><b><a href="/<%=from_user%>"><%=from_user%></a>:</b> <%=text%></p>
</div>
</div>
</script>
*/
//You can also inline script:
/* <script type="text/html" id="user_tmpl">
<% for ( var i = 0; i < users.length; i++ ) { %>
<li><a href="<%=users[i].url%>"><%=users[i].name%></a></li>
<% } %>
</script>
*/
/*
Quick tip: Embedding scripts in your page that have a unknown content-type (such is the case here ? the browser doesn?t know how to execute a text/html script) are simply ignored by the browser ? and by search engines and screenreaders. It?s a perfect cloaking device for sneaking templates into your page. I like to use this technique for quick-and-dirty cases where I just need a little template or two on the page and want something light and fast.
and you would use it from script like so:
*/
var results = document.getElementById("results");
results.innerHTML = tmpl("item_tmpl", dataObject);
/*
You could pre-compile the results for later use. If you call the templating function with only an ID (or a template code) then it?ll return a pre-compiled function that you can execute later:
*/
var show_user = tmpl("item_tmpl"), html = "";
for ( var i = 0; i < users.length; i++ ) {
html += show_user( users[i] );
}
/*
The biggest falling-down of the method, at this point, is the parsing/conversion code ? it could probably use a little love. It does use one technique that I enjoy, though: If you?re searching and replacing through a string with a static search and a static replace it?s faster to perform the action with .split("match").join("replace") ? which seems counter-intuitive but it manages to work that way in most modern browsers. (There are changes going in place to grossly improve the performance of .replace(/match/g, "replace") in the next version of Firefox ? so the previous statement won?t be the case for long.)
Feel free to have fun with it ? I?d be very curious to see what mutations occur with the script. Since it?s so simple it seems like there?s a lot that can still be done with it.
*/
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