TryGhost/express-hbs

express-hbs

Express Handlebars template engine for Express apps, with nested layouts, named content blocks, cached partials, i18n helpers, and asynchronous helpers.

express-hbs exposes Express-compatible view engine functions and a shared Handlebars instance. It is used by apps that want Handlebars templates with layout inheritance and block-style content regions while keeping the familiar app.engine() integration.

Requirements

• Node.js 20 or later
• pnpm 10 when working on this repository

v2.0.0

Version 2 was a rewrite and cleanup, with no known breaking changes. Lots of bugs were fixed which may have subtly changed behaviour.

Full details: https://github.com/TryGhost/express-hbs/releases/tag/2.0.0

v1.0.0 Breaking Changes

If you're upgrading from v0.8.4 to v1.0.0 there are some potentially breaking changes to be aware of:

1. Handlebars @v4.0.5 - please see the handlebars v4.0 compatibility notes
2. The file extension for partial files must now match the extension configured in extname - please see the PR

Usage

Register the engine with Express using hbs.express4().

var hbs = require('express-hbs');

// Use `.hbs` for extensions and find partials in `views/partials`.
app.engine('hbs', hbs.express4({
  partialsDir: __dirname + '/views/partials'
}));
app.set('view engine', 'hbs');
app.set('views', __dirname + '/views');

hbs.express3() is still available for legacy apps and accepts the same options:

app.engine('hbs', hbs.express3({
  partialsDir: __dirname + '/views/partials'
}));

Options for express3() and express4():

hbs.express4({
  partialsDir: "{String/Array} [Required] Path to partials templates, one or several directories",

  // OPTIONAL settings
  restrictLayoutsTo: "{String} Absolute path to a directory to restrict layout directive reading from",
  blockHelperName: "{String} Override 'block' helper name.",
  contentHelperName: "{String} Override 'contentFor' helper name.",
  defaultLayout: "{String} Absolute path to default layout template",
  extname: "{String} Extension for templates & partials, defaults to `.hbs`",
  handlebars: "{Module} Use external handlebars instead of express-hbs dependency",
  i18n: "{Object} i18n object",
  layoutsDir: "{String} Path to layout templates",
  templateOptions: "{Object} options to pass to template()",
  beautify: "{Boolean} whether to pretty print HTML, see github.com/einars/js-beautify .jsbeautifyrc",

  // override the default compile
  onCompile: function(exhbs, source, filename) {
    var options;
    if (filename && filename.indexOf('partials') > -1) {
      options = {preventIndent: true};
    }
    return exhbs.handlebars.compile(source, options);
  }
});

Syntax

To mark where a layout should insert page content:

{{{body}}}

To declare a block placeholder in a layout:

{{{block "pageScripts"}}}

To define block content in a page:

{{#contentFor "pageScripts"}}
  CONTENT HERE
{{/contentFor}}

Layouts

There are three ways to use a layout, listed in precedence order:

1. Declarative within a page. Use handlebars comment

   {{!< LAYOUT}}
   

   Layout file resolution:

   If path starts with '.'
       LAYOUT is relative to template
   Else If `layoutsDir` is set
       LAYOUT is relative to `layoutsDir`
   Else
       LAYOUT from path.resolve(dirname(template), LAYOUT)
   

2. As an option to render

   ⚠️ Passing user-controlled data into the layout option can read arbitrary files unless restrictLayoutsTo confines layout resolution to a safe directory. Do not call res.render('index', req.query) or similar without setting restrictLayoutsTo.

   res.render('veggies', {
     title: 'My favorite veggies',
     veggies: veggies,
     layout: 'layout/veggie'
   });
   

   This option also allows layout suppression, including the default layout and template-declared layouts, by passing a falsey JavaScript value:

   res.render('veggies', {
     title: 'My favorite veggies',
     veggies: veggies,
     layout: null // render without using a layout template
   });
   

   Layout file resolution:

   If path starts with '.'
       layout is relative to template
   Else If `layoutsDir` is set
       layout is relative to `layoutsDir`
   Else
       layout from path.resolve(viewsDir, layout)
   

3. Lastly, use defaultLayout if specified in hbs configuration options.

Layouts can be nested: just include a declarative layout tag within any layout template to have its content included in the declared "parent" layout. Be aware that too much nesting can impact performances, and stay away from infinite loops!

Helpers

Synchronous helpers

hbs.registerHelper('link', function(text, options) {
  var attrs = [];
  for(var prop in options.hash) {
    attrs.push(prop + '="' + options.hash[prop] + '"');
  }
  return new hbs.SafeString(
    "<a " + attrs.join(" ") + ">" + text + "</a>"
  );
});

in markup

{{{link 'barc.com' href='http://barc.com'}}}

Asynchronous helpers

hbs.registerAsyncHelper('readFile', function(filename, cb) {
  fs.readFile(path.join(viewsDir, filename), 'utf8', function(err, content) {
    cb(new hbs.SafeString(content));
  });
});

in markup

{{{readFile 'tos.txt'}}}

i18n support

Express-hbs supports i18n

var i18n = require('i18n');

// minimal config
i18n.configure({
    locales: ['en', 'fr'],
    cookie: 'locale',
    directory: __dirname + "/locales"
});

app.engine('hbs', hbs.express3({
    // ... options from above
    i18n: i18n,  // registers __ and __n helpers
}));
app.set('view engine', 'hbs');
app.set('views', viewsDir);

// cookies are needed
app.use(express.cookieParser());

// init i18n module
app.use(i18n.init);

Engine Instances

Create isolated engine instances with their own cache system and handlebars engine.

var hbs = require('express-hbs');
var instance1 = hbs.create();
var instance2 = hbs.create();

Template options

The main use case for template options is setting the Handlebars data object, which creates global template variables accessible with an @ prefix.

Template options can be passed when creating an engine instance, updated with updateTemplateOptions(templateOptions), or set for one request with updateLocalTemplateOptions(locals, templateOptions) on res.locals.

Both of these methods have a companion method getTemplateOptions() and getLocalTemplateOptions(locals), which should be used when extending or merging the current options.

Example

in File app.js

// http://expressjs.com/api.html#app.locals
app.locals({
    'PROD_MODE': 'production' === app.get('env')
});

File views/layout/default.hbs

<html>
  <head>
    <title>{{title}}</title>
    <link type="text/css" rel="stylesheet" href="/css/style.css"/>
    {{{block "pageStyles"}}}
  </head>
  <body>
    {{{body}}}

    {{> scripts}}

    {{#if PROD_MODE}}
    {{{block 'googleAnalyticsScripts'}}}
    {{/if}}

  </body>
</html>

File views/index.hbs

{{!< default}}

{{#contentFor 'pageStyles'}}
<style>
  .clicker {
    color: blue;
  };
</style>
{{/contentFor}}

<h1>{{title}}</h1>
<p class="clicker">Click me!</p>

To run example project

pnpm install
node example/app.js

The example server listens on http://localhost:3000.

Testing

Install dependencies and run the test suite:

pnpm install
pnpm test

Useful maintainer commands:

pnpm lint          # oxlint plus oxfmt --check
pnpm lint:fix      # apply safe lint fixes and formatting
pnpm coverage      # mocha under nyc with enforced coverage thresholds

Credits

Inspiration and code from donpark/hbs

Big thanks to all CONTRIBUTORS

License

The MIT License (MIT)

Copyright (c) 2012-2026 Barc, Inc., Ghost Foundation - Released under the MIT license.