Handoff HubSpot Client

A transformer CLI that bridges Handoff design system components and HubSpot CMS modules. It fetches component definitions from the Handoff API, validates them against the HubSpot module specification, and transpiles Handlebars templates into complete, ready-to-deploy HubSpot modules.

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How It Works

Handoff publishes design system components as structured JSON payloads that include:

• A Handlebars template (code) describing the component's markup
• A property schema (properties) describing the editable fields
• CSS and JS assets for styles and behavior
• Metadata such as title, description, categories, tags, and versioning

This tool takes those payloads and produces a HubSpot .module folder containing:

File	Description
module.html	HubL template transpiled from the Handlebars source
module.css	Component CSS (or a blank stub when using the central stylesheet)
module.js	Component JavaScript (or a blank stub when using the central bundle)
meta.json	HubSpot module metadata (label, content types, categories, tags)
fields.json	HubSpot field definitions generated from the property schema

Pipeline Overview

Handoff API
    │
    ▼
fetchComponent(id)        → HandoffComponent JSON
    │
    ▼
validateModule(component) → FieldValidation[]  (errors/warnings)
    │
    ▼
transpile(code, props)    → HubL string  (module.html)
buildFields(properties)   → HubSpot field definitions  (fields.json)
buildMeta(component)      → HubSpot module metadata  (meta.json)
    │
    ▼
Write *.module/ folder to disk

Handlebars → HubL Transpilation

HubSpot modules use HubL, a Jinja2-like templating language. Handoff components are authored in Handlebars. The transpiler converts each Handlebars construct to its HubL equivalent:

Variables

Handoff components reference component data under the properties namespace. The transpiler rewrites these to HubSpot's module namespace:

{{properties.headline}}

becomes:

{{ module.headline }}

Conditionals

{{#if properties.show_cta}}
  <a href="...">Click</a>
{{/if}}

becomes:

{% if module.show_cta %} <a href="...">Click</a> {% endif %}

Loops

{{#each properties.items}}
  <li>{{this.label}}</li>
{{/each}}

becomes:

{% for item_i in module.items %} <li>{{ item_i.label }}</li> {% endfor %}

Typed Field Handling

The transpiler is property-schema-aware. The way a variable is output depends on its declared type in the property schema. For example, a button property named cta:

<a href="{{properties.cta.url}}">{{properties.cta.label}}</a>

becomes:

<a href="{{ module.cta_url.href|escape_attr }}">{{ module.cta_text }}</a>

This is because HubSpot represents button/link URLs as a structured url object, requiring the _url.href accessor and escape_attr filter. The transpiler handles these type-specific rewrites automatically for link, button, breadcrumb, image, url, video_embed, and menu types.

Menus

The {{#field menu}} block generates the HubL menu lookup and iteration boilerplate:

{{#field properties.nav}}
  {{#each properties.nav}}
    <li>{{this.label}}</li>
  {{/each}}
{{/field}}

becomes:

{# field properties.nav type="menu"  #}
{% set menu_xxxxx = menu(module.nav) %}
{% for item_n in menu_xxxxx.children %} <li>{{ item_n.label }}</li> {% endfor %}
{# end field #}

Search Fields

The {{#field search}} block injects the standard HubSpot search context variables (search_page, content_types, etc.) required for site search module patterns.

Fields Generation

Each Handoff property type maps to one or more HubSpot field definitions in fields.json:

Handoff type	HubSpot field(s)
text	text
richtext	richtext
number	number (with min, max, step)
boolean	boolean (checkbox display)
select	choice (with choices array)
image	image (responsive, lazy-loaded)
icon	text
link	url field ({id}_url) + text field ({id}_text)
button	url field ({id}_url) + text field ({id}_text, labeled "Label")
url	url (all link types supported)
video_file	file field + text title field ({id}_title)
video_embed	text embed URL + text title ({id}_title) + image poster ({id}_poster)
menu	menu
array	group (with occurrence min/max, children built recursively)
object	group (children built recursively)

Validation

Before transpilation, each component is validated at both the module and field levels.

Module-level checks (errors halt the build unless --force is used):

• code, title, tags, categories, and properties are all required
• Each category must be one of the allowed HubSpot categories

Field-level checks include both errors (build blockers) and warnings (non-blocking):

• Every field must have a valid type, a name, and a rules.required boolean
• A description and default value are required (warnings if missing)
• text and number fields must have rules.content with min/max
• array fields must have rules.content.min/max, items.type, and recursively valid children
• image fields must have rules.dimensions (with min.width/min.height) and a default with src/alt
• link defaults must include href and text; button defaults must include url and label
• select fields must have an options array
• object fields must have a properties map

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Installation

npm install -g handoff-hubspot

Requirements

• Node 20, NPM
• A running Handoff instance (URL to the API)
• A HubSpot account if you intend to deploy the generated modules

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Quick Start

1. Install

   npm install -g handoff-hubspot

2. Configure

   handoff-hubspot config

   This will prompt you interactively for:

   • The URL to your Handoff API (e.g. https://design.example.com/api/)
   • Where to save the shared CSS bundle
   • Where to save the shared JS bundle
   • Whether to use per-module CSS/JS or the central compiled bundles
   • Where to write the generated .module folders
   • A label prefix for modules inside HubSpot (e.g. "UDS: ")
   • Optional HTTP Basic Auth credentials if your Handoff instance requires authentication

   A handoff.config.json file is written to the current working directory.

3. List available components

   handoff-hubspot list

4. Fetch and build a single component

   handoff-hubspot fetch hero-banner

   The module is written to {modulesPath}/hero-banner.module/.

5. Fetch and build all components

   handoff-hubspot fetch:all

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Commands

handoff-hubspot config

Interactively create or overwrite handoff.config.json.

handoff-hubspot list

List all components available from the Handoff API.

handoff-hubspot docs [component]

Open the Handoff documentation page for a component in the browser.

handoff-hubspot styles

Fetch the shared CSS bundle (main.css) from the Handoff API and write it to cssPath.

handoff-hubspot scripts

Fetch the shared JS bundle (main.js) from the Handoff API and write it to jsPath. Skipped automatically when moduleJS is true.

handoff-hubspot fetch [component]

Fetch a single component, validate it, transpile it, and write the .module folder. Use --force (-f) to build even when validation errors are present.

handoff-hubspot validate [component]

Fetch a single component and run validation only (no files are written).

handoff-hubspot validate:all

Fetch and validate every component. Exits with a non-zero code if any component fails validation.

handoff-hubspot fetch:all [--force]

Validate and build every component. Without --force, aborts the entire run if validation fails.

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Configuration Reference (handoff.config.json)

Key	Type	Default	Description
url	string	https://localhost:3000/api/	Base URL of the Handoff API
cssPath	string	css/uds.css	Directory for the shared CSS output
jsPath	string	js/uds.js	Directory for the shared JS output
modulesPath	string	modules	Directory where .module folders are written
modulePrefix	string	UDS:	Prefix prepended to each module's label in HubSpot
moduleCSS	boolean	true	When true, writes per-module CSS; when false, writes a blank stub
moduleJS	boolean	false	When true, writes per-module compiled JS; when false, writes a blank stub
username	string	""	HTTP Basic Auth username (optional)
password	string	""	HTTP Basic Auth password (optional)
import	object	(absent)	Per-component-type import rules (see below)

Import Configuration

The import key controls which components are transpiled and how. It replaces the previous hubdb_mappings, componentJS, and componentCSS top-level keys.

Each key under import corresponds to a Handoff component type (e.g. "element", "block", "data"). The value is either a boolean or an object with per-component overrides:

{
  "import": {
    "element": false,
    "block": {
      "accordion": false
    },
    "data": {
      "bar_chart": {
        "type": "hubdb",
        "target_property": "data",
        "mapping_type": "xy"
      },
      "category_breakdown_chart": {
        "type": "hubdb",
        "target_property": "data",
        "mapping_type": "multi_series"
      }
    }
  }
}

Semantics:

Config value	Effect
import.{type}: false	Skip all components of that type
import.{type}: true (or key absent)	Import all components of that type normally
import.{type}: { id: false }	Import all of that type except those set to false
import.{type}: { id: { type: "hubdb", ... } }	Import with HubDB data mapping
import.{type}: { id: { js: true } }	Per-component JS override (fetches JS even when moduleJS is false)
import.{type}: { id: { css: true } }	Per-component CSS override (fetches CSS even when moduleCSS is false)

When import is absent entirely, all components are imported normally.

HubDB Data Mappings

When a component entry under import has "type": "hubdb", the build pipeline treats its target_property field as a HubDB-powered data source rather than a static array. Two fields are required:

Key	Description
target_property	The name of the array/object property in the component schema to map (e.g. "data")
mapping_type	Either "xy" (two-column x/y data) or "multi_series" (multiple named series with categories)

What happens at build time:

1. A Data Source choice field is auto-generated with two options: "Query Builder" and "Manual Data" (default). This field is always visible in the HubSpot editor and does not depend on any field defined in Handoff.
2. A Query Config field group is injected, visible only when "Query Builder" is selected. It contains fields for table selection, column mapping, sorting, limits, and a diagnostic toggle.
3. The target array field (e.g. data) is annotated with a visibility rule so it only appears when "Manual Data" is selected.
4. The transpiler rewrites all Handlebars references to the target property as component_data and prepends HubL code that queries HubDB when in query mode, falling through to the manual array otherwise.

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Module Output Structure

Each component produces a folder at {modulesPath}/{component-id}.module/:

hero-banner.module/
├── module.html    # HubL template (transpiled from Handlebars)
├── module.css     # Component CSS
├── module.js      # Component JavaScript
├── meta.json      # HubSpot module metadata
└── fields.json    # HubSpot field definitions

module.html opens with a comment block containing the original component metadata:

{#
  title: Hero Banner
  description: A full-width hero with headline, body copy, and CTA button
  group: Marketing
  version: 1.4.2
  last_updated: 2026-03-11T00:00:00.000Z
  link: https://design.example.com/system/component/hero-banner
#}

Navigation components (group "Navigation") are automatically marked as global: true in meta.json.