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handlebars-lang/handlebars.js

★ 18,631JavaScriptAudience · developerComplexity · 2/5ActiveLicenseSetup · easy

TLDR

A JavaScript templating library that fills in placeholders in text templates with data, supporting helpers, loops, conditionals, and reusable fragments.

Mindmap

mindmap
  root((repo))
    What it does
      Fill templates with data
      Generate HTML strings
      Precompile templates
    Key features
      Helpers and functions
      Loops and conditionals
      Nested data access
      Reusable partials
    Environments
      Browser support
      Node.js support
      CDN delivery
    Use cases
      Server-side rendering
      Client-side rendering
      Email templates
      Dynamic content

Things people build with this

USE CASE 1

Generate HTML pages by combining templates with user data on the server or in the browser.

USE CASE 2

Create reusable email templates with dynamic content like names, dates, and personalized messages.

USE CASE 3

Build dynamic web pages that render different content based on conditional logic and loops in templates.

USE CASE 4

Precompile templates into JavaScript functions for faster page loads without runtime parsing overhead.

Tech stack

JavaScriptNode.jsnpm

Getting it running

Difficulty · easy Time to first run · 5min
Use freely for any purpose, including commercial use, as long as you keep the copyright notice.

In plain English

Handlebars.js is a JavaScript templating library, a tool for combining a template (a text pattern with placeholders) with data to produce a final string of HTML or any other text. You write a template with double-curly-brace markers like {{name}} or {{hometown}}, compile it into a function, then call that function with a data object to fill in the blanks. Handlebars extends an older, simpler templating format called Mustache. It keeps Mustache's basic syntax but adds features that make templates more powerful: helpers (custom functions you can call from templates), block expressions (structures like if/else and loops), nested path lookups (accessing deeply nested data with dot notation), and partials (reusable template fragments). Templates can be precompiled into JavaScript functions before deployment, which makes pages load faster since no parsing is needed at runtime. The library works in both browsers and Node.js. It is available via npm and can also be loaded from a content delivery network. Handlebars is widely used in projects that need to generate HTML from data, both on the server and in the browser.

Copy-paste prompts

Prompt 1
Show me how to write a Handlebars template that loops through an array of products and displays their names and prices.
Prompt 2
How do I create a custom Handlebars helper that formats a date string into a readable format?
Prompt 3
Write a Handlebars template with an if/else block that shows different messages based on whether a user is logged in.
Prompt 4
How do I precompile Handlebars templates and use them in a Node.js application?
Prompt 5
Show me how to use Handlebars partials to create a reusable header and footer for multiple templates.
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Generated 2026-05-18 · Model: sonnet-4-6 · Verify against the repo before relying on details.