Deno config

Default configuration for Deno by Lume

After running deno run -A https://lume.land/init.ts to initialize a new Lume project, the file deno.json is created automatically. This file is loaded by Deno and contains the configuration for Deno tools like tasks, imports, linter, permissions, etc.

After creating the file, you can edit it to adapt for your needs (go to deno.com for a complete documentation). This is a simple explanation, especially intended for people not familiar enough with how Deno works.

The JSON file has the following properties:

Imports

The imports property contains a map with specifiers and the URL to resolve them:

{
  "imports": {
    "lume/": "https://cdn.jsdelivr.net/gh/lumeland/lume@3.1.4/"
  }
}

In this example, we have the lume/ entry mapped to the URL https://cdn.jsdelivr.net/gh/lumeland/lume@3.1.4/. This allows for importing Lume with:

import lume from "lume/mod.ts";

and Deno automatically resolves the full URL (https://cdn.jsdelivr.net/gh/lumeland/lume@3.1.4/mod.ts). This makes it pretty easy to change the version of Lume because you only need to change this URL. It's even possible to map Lume to a local folder, for debug purposes.

{
  "imports": {
    "lume/": "../my-lume-clone/"
  }
}

Lume by default adds also the lume/jsx-runtime (required for JSX) and lume/cms/ (if you are using LumeCMS). More info about the Import map standard.

Tasks

The tasks property defines some commands (known as tasks) to be executed with deno task [name]. Lume creates three tasks:

  • lume: It's the base task used by the other tasks. It runs the lume/cli.ts module (resolved to the URL defined in the imports).
  • build: It builds the site for production. The command simply runs lume task, but the idea is to have a more explicit name (build instead of the generic lume) and having two tasks separated makes it easier to add extra flags to the build process without modifying the base task (like a custom location, environment variables, etc).
  • serve: It runs the lume task but with the -s flag (to start a local development server). It's intended for local development.

Unstable

The unstable property enables some Deno features that are disabled by default because they are unstable. Lume enables temporal (to use the Temporal global object to work with dates) and fmt-components (to format .vto files when you run deno fmt).

Lock

Deno, by default, creates a deno.lock file to check external module integrity. The problem is that this file generates a lot of conflicts, especially when working with git branches. Another problem is that it doesn't delete old imports. For example, if you're using Lume 3.1.0 and upgrade to Lume 3.1.1, the lock file will contain both versions. Lume by default disables the creation of this file with the property "lock": false. Remove this line if you want to enable it.

Compiler options

This property configures TypeScript and JSX for Deno. Lume configures JSX to use lume (resolved to lume/jsx-runtime) for JSX and MDX files and loads the Lume types so you can use the Lume global namespace.

Lint

Deno has a built-in linter that automatically checks your files and detects issues. Lume adds a rule to check the order of the plugins in the _config.ts file to warn about possible issues (for example, some plugins should be registered before others to prevent unexpected behaviors). It also disables the no-import-prefix (enabled by default by Deno) because it's too aggressive and doesn't work well with HTTP imports.

Permissions

This property contains permissions sets that can be used with the flag -P. For example, the task lume has the option -P=lume, to use the lume permission set.

By default, the lume set grants permissions to read, write (only in the current folder), access to environment variables, run commands, ffi, and access to some sys info.

The import property limits the domains from where you can import modules (jsdelivr.com, jsr.io, deno.land, and esm.sh by default). To import modules from other domains, you can add the domain name to this list, or use "import": true if you don't want to delimit the domains.

net permissions are granted only for 0.0.0.0 (to create local servers) and jsr.io, *.jsdelivr.net, and npmjs.org (needed to download dependencies from JSR and NPM).

Some plugins need to change the permissions to work. For example, Google Fonts requires adding the Google CDN to the net property to download the fonts.

Not everybody needs this level of security. If you don't want to deal with permissions errors, you can allow everything with:

{
  "permissions": {
    "lume": {
      "all": true
    }
  }
}
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