Handlebars provides the power necessary to let you build semantic templates effectively with no frustration. Handlebars is largely compatible with Mustache templates. In most cases it is possible to swap out Mustache with Handlebars and continue using your current templates.
Checkout the official Handlebars docs site at handlebarsjs.com and try our live demo.
See our installation documentation.
In general, the syntax of Handlebars.js templates is a superset of Mustache templates. For basic syntax, check out the Mustache manpage.
Once you have a template, use the Handlebars.compile
method to compile
the template into a function. The generated function takes a context
argument, which will be used to render the template.
var source = "<p>Hello, my name is {{name}}. I am from {{hometown}}. I have " +
"{{kids.length}} kids:</p>" +
"<ul>{{#kids}}<li>{{name}} is {{age}}</li>{{/kids}}</ul>";
var template = Handlebars.compile(source);
var data = { "name": "Alan", "hometown": "Somewhere, TX",
"kids": [{"name": "Jimmy", "age": "12"}, {"name": "Sally", "age": "4"}]};
var result = template(data);
// Would render:
// <p>Hello, my name is Alan. I am from Somewhere, TX. I have 2 kids:</p>
// <ul>
// <li>Jimmy is 12</li>
// <li>Sally is 4</li>
// </ul>
Full documentation and more examples are at handlebarsjs.com.
Handlebars allows templates to be precompiled and included as javascript code rather than the handlebars template allowing for faster startup time. Full details are located here.
Handlebars.js adds a couple of additional features to make writing templates easier and also changes a tiny detail of how partials work.
Block expressions have the same syntax as mustache sections but should not be confused with one another. Sections are akin to an implicit each
or with
statement depending on the input data and helpers are explicit pieces of code that are free to implement whatever behavior they like. The mustache spec defines the exact behavior of sections. In the case of name conflicts, helpers are given priority.
There are a few Mustache behaviors that Handlebars does not implement.
compat
flag must be set to enable this functionality. Users should note that there is a performance cost for enabling this flag. The exact cost varies by template, but it's recommended that performance sensitive operations should avoid this mode and instead opt for explicit path references.{{
and a command character such as #
, /
or >
. The command character must immediately follow the braces, so for example {{> partial }}
is allowed but {{ > partial }}
is not.Handlebars has been designed to work in any ECMAScript 2020 environment. This includes
If you need to support older environments, use Handlebars version 4.
In a rough performance test, precompiled Handlebars.js templates (in the original version of Handlebars.js) rendered in about half the time of Mustache templates. It would be a shame if it were any other way, since they were precompiled, but the difference in architecture does have some big performance advantages. Justin Marney, a.k.a. gotascii, confirmed that with an independent test. The rewritten Handlebars (current version) is faster than the old version, with many performance tests being 5 to 7 times faster than the Mustache equivalent.
See release-notes.md for upgrade notes.
If you are using Handlebars in production, please regularly look for issues labeled possibly breaking. If this label is applied to an issue, it means that the requested change is probably not a breaking change, but since Handlebars is widely in use by a lot of people, there's always a chance that it breaks somebody's build.
See FAQ.md for known issues and common pitfalls.
Have a project using Handlebars? Send us a pull request!
Handlebars.js is released under the MIT license.