marten-importmap v0.1.2

MartenImportmap

Integration between Marten and the ImportMap shard.

Installation

Add the shard to your shard.yml:

dependencies:
  marten_importmap:
    github: treagod/marten-importmap

Run shards install, then add the two requires to your project:

# src/project.cr
require "marten"
require "marten_importmap"

# src/cli.cr  (needed before running `marten importmap init`)
require "marten/cli"
require "marten_importmap/cli"

Then initialize the project:

marten importmap init

marten importmap init will:

  • add require "marten_importmap" to src/project.cr if not present
  • add require "marten_importmap/cli" to src/cli.cr if the file exists and the require is missing
  • add MartenImportmap::App to config.installed_apps
  • create config/initializers/importmap.cr for user-managed importmap entries
  • create config/initializers/importmap_pins.cr for CLI-managed pins
  • create src/assets/application.js if it does not exist

Template tag

Add {% importmap %} inside the <head> of your base template. It renders the <script type="importmap"> block and a <script type="module"> tag for the entrypoint:

<head>
  <link rel="stylesheet" href="{% asset 'css/app.css' %}" />
  {% importmap %}
</head>

Optional arguments:

{% importmap %}                                  {# default namespace, entrypoint "application" #}
{% importmap "admin" %}                          {# custom namespace #}
{% importmap "admin" entrypoint="admin/app" %}   {# custom namespace and entrypoint #}

Configuration

Marten.configure do |config|
  # Default: false (download resolved modules into vendor_scripts_dir)
  config.importmap.keep_cdn_urls = false

  # Default: "src/assets/vendor/"
  config.importmap.vendor_scripts_dir = "src/assets/vendor/"

  config.importmap.draw do
    pin "application", "application.js"
  end
end

Use config/initializers/importmap.cr for manual pins, namespaces, and pin_all_from directives.

CLI

After initialization, pin a library using JSPM:

marten importmap pin react
marten importmap pin react --from jsdelivr

Supported providers: jspm.io (default), jsdelivr, unpkg, skypack, esm.sh.

The command downloads the resolved module to src/assets/vendor/ and updates config/initializers/importmap_pins.cr:

# AUTO-GENERATED by `marten importmap pin ...`
# DO NOT EDIT.

Marten.configure do |config|
  config.importmap.draw do
    pin "react", "vendor/react.js"
  end
end

config/initializers/importmap_pins.cr is CLI-managed. config/initializers/importmap.cr remains user-managed.

Repository

marten-importmap

Owner
Statistic
  • 0
  • 0
  • 0
  • 1
  • 4
  • 7 days ago
  • February 5, 2026
License

MIT License

Links
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Thu, 26 Mar 2026 09:30:17 GMT

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