Deno Runtime

EXPERIMENTAL: It's early days yet for Deno and how Stencil will work with it, so we'll label this experimental.

Traditionally, Stencil and many of today's CLIs for the web ecosystem run on top of Node. The Stencil compiler, however, is not locked down to only a Node environment, but rather it can execute from any JavaScript runtime, such as a browser main thread, web worker thread, or the latest JS runtime Deno! Deno is a simple, modern and secure runtime for JavaScript and TypeScript that uses V8 and is built in Rust.

Stencil's architecture allows it to be passed a system (sys) that interacts with the runtime. For example, Node's fs will use readdir() and must be passed a callback, whereas Deno uses readDir() (has a capital D) and returns a promise. The same concept is applied to the browser and web worker systems, which allows the compiler to stay generic and versatile for any JS runtime.

Installing Deno Stencil CLI

The Stencil compiler, and its Command-Line Interface (CLI), can also be executed with Deno, but it works differently than a traditional Node CLI. The biggest difference is that Deno does not have a centralized package manager, so Deno doesn't have an npm equivalent.

With Deno there is no npm install command, but instead you specify the external URL of the executable script to install. After installing Deno, run the command:

deno install -n stencil --allow-read --allow-write --allow-net https://stencil.docschina.org/cli.ts

Let's break this down a little further to explain what this command is doing:

Command / Arg	Description
`deno`	The Deno command already installed .
`install`	Installer script argument.
`-n`	The name you'll give the executable your installing.
`stencil`	`stencil` is the name of the executable in this example, but can be customized to to whatever you'd like.
`--allow-read`	The CLI will need to access files, so this option allows it to read local files.
`--allow-write`	The CLI will also need to write files.
`--allow-net`	The CLI will need to access the net to install dependencies.
`https://stencil.docschina.org/cli.ts`	The location of the Stencil's Deno installer.

Don't worry, this command doesn't need to be ran everytime you're running Stencil with Deno, but instead it's just installing it, and giving your machine the executable name of stencil. During the installing you'll see where additional script files are coming from, which in our case is https://cdn.jsdelivr.net/npm/.

After installing you'll then have the global stencil command ready to be used and you can test it out by running the CLI's help command:

stencil help

Updating Deno Stencil CLI

To update the installed Deno Stencil CLI, add the -f option to "force" overwriting the existing executable and reinstalling the latest.

deno install -n stencil --allow-read --allow-write --allow-net -f https://stencil.docschina.org/cli.ts

Running Deno Stencil CLI

After the installer script has successfully ran, the stencil executable is ready to be used with the same options as the Node CLI. See the CLI docs for all available options or run stencil help.

Even though stencil is now a global executable, its goal is still aimed at running each individual application's local Stencil version. The installed command is simply the entry, but it's not locked into a specific compiler version. When the stencil command is ran, it looks to use the locally installed install Stencil compiler, and if one isn't already installed, it'll dynamically load the latest Stencil version.

The Deno CLI is still experimental, the generate command has not been ported yet.

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