Syntax Reference¶

This page covers all supported Handlebars template syntax.

Variable Interpolation¶

Use double curly braces to output a value:

{{name}}

Values are output as-is by default. When auto_escape=True is enabled, values are HTML-escaped. Triple-stache and & always output unescaped content regardless of the auto_escape setting:

{{{rawHtml}}}
{{&rawHtml}}

Paths¶

Dot Notation¶

Access nested properties with dots:

{{person.name}}
{{article.author.name}}

Slash Notation¶

Slashes work the same as dots:

{{person/name}}

`this` Keyword¶

Refer to the current context:

{{this}}
{{this.name}}
{{./name}}

Parent Scope¶

Access parent contexts with ../:

{{#each items}}
  {{../title}} - {{name}}
{{/each}}

Multiple levels work too: {{../../grandparent}}.

`@data` Variables¶

Special variables prefixed with @:

Variable	Description
`@root`	The root context
`@index`	Current array index (in `#each`)
`@key`	Current object key (in `#each`)
`@first`	`true` for the first iteration
`@last`	`true` for the last iteration

{{#each items}}
  {{@index}}: {{this}}
{{/each}}

Literals¶

Use literal values directly in expressions:

{{helper "string"}}
{{helper 'single quoted'}}
{{helper 42}}
{{helper 3.14}}
{{helper true}}
{{helper false}}
{{helper null}}
{{helper undefined}}

Comments¶

Comments are stripped from output:

{{! This is a short comment }}
{{!-- This is a long comment
  that can span multiple lines --}}

Whitespace Control¶

Add ~ to strip whitespace on that side of a tag:

{{~expression}}   {{!-- strips whitespace before --}}
{{expression~}}   {{!-- strips whitespace after --}}
{{~expression~}}  {{!-- strips both sides --}}

This works on all tag types including blocks:

{{~#each items~}}
  {{this}}
{{~/each~}}

Block Helpers¶

Block helpers wrap a section of the template:

{{#if condition}}
  Rendered when truthy
{{/if}}

Inverse / Else¶

Use {{else}} or {{^}} for the inverse block:

{{#if condition}}
  Truthy
{{else}}
  Falsy
{{/if}}

{{#if condition}}
  Truthy
{{^}}
  Falsy (same as else)
{{/if}}

Chained Else¶

Chain conditions with {{else if}}:

{{#if a}}
  A is truthy
{{else if b}}
  B is truthy
{{else}}
  Neither
{{/if}}

Block Parameters¶

Capture block values with as |param|:

{{#each items as |item index|}}
  {{index}}: {{item.name}}
{{/each}}

{{#with person as |p|}}
  {{p.name}}
{{/with}}

Hash Arguments¶

Pass named arguments to helpers:

{{helper key="value" count=42}}

Subexpressions¶

Nest helper calls as arguments using parentheses:

{{helper (subhelper arg)}}
{{#if (eq status "active")}}
  Active!
{{/if}}

Raw Blocks¶

Raw blocks pass content through without processing:

{{{{raw}}}}
  {{this is not processed}}
{{{{/raw}}}}

The content between raw block tags is output as-is.

Escaped Delimiters¶

To output literal {{, escape with a backslash:

\{{not a variable}}

This renders as {{not a variable}}.