Handlebars Templating Language

Overview

The Handlebars Templating Language is available for use with Andi PrintPowers and EmailPowers. Both follow the same pattern of feeding data to the power along with the template to produce an HTML output. In the case of PrintPowers a fileId is used as a reference to the generated HTML content for custom print outs and the with EmailPowers the resulting HTML is sent as an email.

In this Article

• Escaping Handlebars Expressions
• Language Features
• HTML Escaping
• Whitespace Control
• Built-In Helpers
• Extensibility

Escaping Handlebars Expressions

\{{escaped}}
{{{{raw}}}}
{{escaped}}

{{{{/raw}}}}

Language Features

Simple Expressions

<p>{{firstname}} {{lastname}}</p>

Model

{
firstname: "Yehuda",
lastname: "Katz",
}

Output

<p>Yehuda Katz</p>

Nested Input Objects

Template

{{person.firstname}} {{person.lastname}}

Model

{
person: {
  firstname: "Yehuda",
  lastname: "Katz",
}
}

Yehuda Katz

{{#with person}}
{{firstname}} {{lastname}}
{{/with}}

{
  person: {
    firstname: "Yehuda",
    lastname: "Katz",
  },
}

Yehuda Katz

{{#each people}}
    {{../prefix}} {{firstname}}
{{/each}}

{
  people: [
    { firstname: "Nils" },
    { firstname: "Yehuda" },
  ],
  prefix: "Hello",
}

Hello Nils
Hello Yehuda

//empty model
{}

HTML Escaping

Template

raw: {{{specialChars}}}
html-escaped: {{specialChars}}

Model 

{ specialChars: "& < \" ' ` =" }

Output

raw: & < " ' ` =
html-escaped: & < " ' ` =

Whitespace Control

Template

{{#each nav ~}}
  
    {{~#if test}}
      {{~title}}
    {{~^~}}
      Empty
    {{~/if~}}
  
{{~/each}}

Model

{
  nav: [{ url: "foo", test: true, title: "bar" }, { url: "bar" }];
}

Output

Versus no Whitespace Control with same model.

Template

{{#each nav}}
  
    {{#if test}}
      {{title}}
    {{^}}
      Empty
    {{/if}}
  
{{~/each}}

Output

Built-In Helpers

#if

Template

Model

{
  author: true,
  firstName: "Yehuda",
  lastName: "Katz",
}

Output

#unless

Template

Model

//empty model
{}

Output

#each

Template

Model

{
  people: [
    "Yehuda Katz",
    "Alan Johnson",
    "Charles Jolley",
  ],
}

Output

#with

Template

{{#with person}}
  {{firstname}} {{lastname}}
{{/with}}

Model

{
  person: {
    firstname: "Yehuda",
    lastname: "Katz",
  },
}

Output

Yehuda Katz

#lookup

Template

{{#each people}}
   {{.}} lives in {{lookup ../cities @index}}
{{/each}}

Model

{
  people: ["Nils", "Yehuda"],
  cities: [
    "Darmstadt",
    "San Francisco",
  ],
}

Output

Nils lives in Darmstadt
Yehuda lives in San Francisco

Extensibility

Partials

{{#*inline "myPartial"}}
  My Content
{{/inline}}
{{#each people}}
  {{myPartial}}
{{/each}}

Model

{
  people: [
    { firstname: "Nils" },
    { firstname: "Yehuda" },
  ],
}

Output

My Content
My Content

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