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Marionette.TemplateCache

The TemplateCache provides a cache for retrieving templates from script blocks in your HTML. This improved the speed of subsequent calls to get a template.

Documentation Index

Basic Usage

To use the TemplateCache, call the get method on TemplateCache directly. Internally, instances of the TemplateCache class will be created and stored but you do not have to manually create these instances yourself. get will return a compiled template function.

var Mn = require('backbone.marionette');

var template = Mn.TemplateCache.get("#my-template", {option: 'value'});
// use the template
template({param1:'value1', paramN:'valueN'});

Making multiple calls to get the same template will retrieve the template from the cache on subsequence calls.

Clear All Templates from Cache

You can clear one or more, or all items from the cache using the clear method. Clearing a template from the cache will force it to re-load from the DOM (via the loadTemplate function which can be overridden, see below) the next time it is retrieved.

If you do not specify any parameters, all items will be cleared from the cache:

var Mn = require('backbone.marionette');

Mn.TemplateCache.get("#my-template");
Mn.TemplateCache.get("#this-template");
Mn.TemplateCache.get("#that-template");

// clear all templates from the cache
Mn.TemplateCache.clear()

Clear Specific Templates from Cache

To clear only specific templates from the cache, specify the jQuery selector that was passed in get to your clear call:

var Mn = require('backbone.marionette');

// Pre-load our cache
Mn.TemplateCache.get("#my-template");
Mn.TemplateCache.get("#this-template");
Mn.TemplateCache.get("#that-template");

// clear 2 of 3 templates from the cache
Mn.TemplateCache.clear("#my-template", "#this-template")

Customizing Template Access

If you want to use an alternate template engine while still taking advantage of the template caching functionality, or want to customize how templates are stored and retrieved, you will need to customize the TemplateCache object. The default operation of TemplateCache, is to retrieve templates from the DOM based on the containing element's id attribute, and compile the html in that element with the underscore.js template function.

Override Template Retrieval

The default template retrieval is to select the template contents from the DOM using jQuery. If you wish to change the way this works, you can override the loadTemplate method on the TemplateCache object.

var Mn = require('backbone.marionette');

var myTemplateFunc = function(selector) {
  // custom template logic
};

Mn.TemplateCache.prototype.loadTemplate = function(templateId, options){
  // load your template here, returning the data needed for the compileTemplate
  // function. For example, you have a function that creates templates based on the
  // value of templateId
  var myTemplate = myTemplateFunc(templateId);

  // send the template back
  return myTemplate;
};

Override Template Compilation

The default template compilation passes the results from loadTemplate to the compileTemplate function, which returns an underscore.js compiled template function. When overriding compileTemplate remember that it must return a function which takes an object of parameters and values and returns a formatted HTML string.

var Handlebars = require('handlebars');
var Mn = require('backbone.marionette');

Mn.TemplateCache.prototype.compileTemplate = function(rawTemplate, options) {
  // use Handlebars.js to compile the template
  return Handlebars.compile(rawTemplate);
};
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