Deno: How to substitute npm scripts (package.json)

Question

Since it is not necessary to have package.json file with deno, how can I as a developer have a similar experience just as we have with npm scripts in package.json?

Answer 1

velociraptor may be of help, especially if you want to run arbitrary shell scripts.

It accepts yaml, json and ts script configuration files. The following example illustrates the main features:

# scripts.yaml
scripts:

  start: deno run server.ts # Scripts can be simple command strings

  opts:                     # Or objects
    cmd: deno run server.ts
    desc: Starts the server
    tsconfig: tsconfig.json # Deno cli options
    imap: importmap.json
    allow:
      - read
      - net
    env:                    # Env vars
      PORT: 8080

  compact: server.ts        # `deno run` is automatically prepended
                            # when the script starts with a .ts file

  multiple:                 # Lists of commands are executed in series
    - echo one
    - echo two

  concurrent:               # Use the pll property to declare
    pll:                    # concurrent scripts
      - echo one
      - echo two

env:                        # Top level options are sent to all the scripts
  PORT: 3000
allow:
  - write

Run vr without arguments to see a list of available scripts. To execute a script run:

$ vr <script name> [additional args]...
# or
$ vr run <script name> [additional args]...
# Additional args are passed to the script

ie

vr start

---

Disclaimer: I'm the author

Answer 2

deno install

You can create executable, aliased scripts with deno install.

It will provide a thin shell/cmd wrapper for the specified main module and CLI arguments. Example:

deno install --root . -n serve --allow-read --allow-net https://deno.land/[email protected]/http/file_server.ts

The result is a serve script, similar to npm "scripts": { "serve": ... }:

./bin/serve # run `serve` script (~ npm run serve)

If the project's bin folder is added to PATH environment, the command shortens up to serve.

What deno install does

• creates bin folder, if not existent
• adds serve/serve.cmd file with following content (Windows here):

  % generated by deno install %
  

@deno.exe "run" "--allow-read" "--allow-net" "https://deno.land/[email protected]/http/file_server.ts" %* ```

• -n is the command name used later on (can be left out)
• --root specifies the bin root location (otherwise ~/.deno)
• -f option overwrites an existent alias

Side note: Any .js/.ts script is a valid reference - source code location (local/URL) does not matter. If external shell scripts are to be included, you can also run them inside a subprocess.

Example: Custom npm run build

// ./scripts/build.ts

// create subprocess
const p = Deno.run({
  cmd: ["deno", "cache", "-r", "--unstable", "main.ts"],
});

await p.status();

deno install --root . --allow-run scripts\build.ts

./bin/build # execute build script

Built-in deno commands

Deno already comes with built-in solutions for common ecosystem tasks, e.g. bundle, fmt, test and lint later on (see deno help). You can invoke these commands directly - no need to define custom scripts:

deno test
deno fmt
deno cache -r main.ts # similar to `npm run build` / `tsc`
# ...