key

typedef

A named reference to a value in the scope or helper scope in a template.

`key`

Looks up a value in the scope or helper scope. This results in a KeyLookup Expression. KeyLookup Expression expressions can provide different values depending on what type of expression they are within. These rules are detailed in KeyLookup Expression.

{{name}}
{{#canVote(age)}}

`EXPRESSION.key`

Looks up key on the result of a subexpression EXPRESSION.

{{person.first.name}}
{{#if tasks.completed().length}} ... {{/if}}

`a\\.single\\.key`

Looks up a value without reading intermediate properties.

{{meta\\.data}}

This is deprecated. If you do have properties with dots in them, use a Bracket Expression:

{{["meta.data"]}}

Use

A key references a value within the scope of a template being rendered. In the following example, the key is name:

<h1>{{name}}</h1>

If this template is rendered with:

{
  name: "Austin"
}

The template writes out:

<h1>Austin</h1>

A scope is a collection of multiple contexts. By default, a key walks up the scope to each context until it finds a value. For example, a template like:

{{first}} {{last}}
  {{#children}}
    {{first}} {{last}}
  {{/children}}

Rendered with:

{
  first: "Barry", last: "Meyer",
  children: [
    {first: "Kim", last: "Sully"},
    {first: "Justin"},
  ]
}

Writes out:

Barry Meyer
    Kim Sully
    Justin Meyer

When last is looked up on the {first: "Justin"} object and not found, it will then try to read the parent context's last property. This is why "Justin Meyer" is written out.