An alternative to npm scripts for Deno

An alternative to npm scripts for Deno

Velociraptor is a script runner for Deno, inspired by npm's package.json scripts. It offers a similar experience but with out-of-the-box support for declarative deno cli options, environment variables, concurrency and (soon) git hooks.

Velociraptor is a script runner for Deno, inspired by npm's package.json scripts. It offers a similar experience but with out-of-the-box support for declarative deno cli options, environment variables, concurrency and (soon) git hooks.


Deno doesn't have a dedicated package manager like npm. While this simplifies many aspects of development, working without the added tooling that npm comes with (such as scripts) may turn out to be challenging: as projects grow Deno cli commands can become quite long and difficult to track and there's not an easy way to share workflow scripts, git hooks and external tooling with collaborators. Velociraptor tries to provide a relatively lightweight solution to these problems by expanding the concept of npm scripts.



$ deno install -qA -n vr[email protected]/cli.ts


$ deno install -qA -n vr[email protected]/cli.ts


To upgrade from an older version run the above commands with the -f flag.

To get help with the CLI run vr --help, or vr <SUBCOMMAND> --help for specific commands.

Project status

πŸ‘¨β€πŸ’» WIP: until the Deno std library is stable there may be breaking changes here, use carefully and feel free to open an issue if you find a bug.

Script files

To get started, create a file called scripts.yaml or velociraptor.yaml in your project folder:

# scripts.yaml
  start: deno run --allow-net server.ts
  test: deno test --allow-net server_test.ts

.json and .ts config files are supported as well:

// scripts.json
  "scripts": {
    "start": "deno run --allow-net server.ts",
    "test": "deno test --allow-net server_test.ts"
// scripts.ts
import { ScriptsConfiguration } from "[email protected]/mod.ts";

export default <ScriptsConfiguration>{
  scripts: {
    start: "deno run --allow-net server.ts",
    test: "deno test --allow-net server_test.ts",

Basic scripts

In its simplest form, the scripts property behaves like in package.json: the keys are script names and the values are the command strings.

Compact deno run

When a command starts with a .ts or .js file, deno run is automatically prepended:

  start: server.ts # Equivalent to `deno run server.ts`

More script options

Scripts can also be objects:

    desc: Runs the server
    cmd: deno run --allow-net server.ts

In this case the command(s) are specified in the cmd property. Use the desc property to provide a description of what the script does, it'll be shown in the list of available scripts (when running vr without arguments).

πŸ‘‡ The following properties can be specified both in script objects and at top-level, in which case they are applied to all the scripts defined in the file. Deno options are effectively only applied to deno commands that accept them.

Environment variables

Environment variables can be specified in the env mapping.

# Env vars specified here are sent to
# all the scripts
  PORT: 8081

    cmd: deno run --allow-net server.ts
    env: # and these are script-specific
      PORT: 8082


Deno permissions can be specified using allow.

# `allow` can be a list of boolean flags
  - net
  - read

    cmd: server.ts
    allow: # or a map


Use the watch property to watch for file changes and restart processes automatically.

Only local files from entry point module graph are watched

    cmd: server.ts
    watch: true


To specify a tsconfig, set the tsconfig property.

    cmd: server.ts
    tsconfig: tsconfig.json

Import maps

Import maps are specified in imap.

    cmd: deno run --unstable server.ts
    imap: importmap.json

πŸ§ͺ Import maps are currently marked as unstable so the --unstable flag must be provided (see other boolean flags).


inspect and inspectBrk correspond to the --inspect and --inspect-brk options.

    cmd: server.ts


The lock property sets the namesake deno option.

    cmd: server.ts
    lock: lock.json

⚠️ Setting this option doesn't create a lock file: you will have to create/update it by passing the --lock-write option manually to your script at the appropriate time. More info here.


Reload source code cache (recompile TypeScript).

    cmd: server.ts
    reload: true                  # Reload everything
    reload: # Reload only standard modules
    reload:                       # Reload specific modules

Other boolean flags

The --cached-only, --no-check, --no-remote, --quiet, --unstable options can be applied using the following properties:

    cmd: server.ts
    cahcedOnly: true
    noCheck: true
    noRemote: true
    quiet: true
    unstable: true


The log property corresponds to deno's --log-level. The allowed values are debug and info.

    cmd: server.ts
    log: debug


Specify a PEM certificate for http client in cert.

    cmd: server.ts
    cert: certificate.pem

V8 flags

V8 flags can be specified like permissions under the v8Flags property.

  - expose-gc
  - async-stack-trace

    cmd: server.ts
      logfile: v8.log

Compound commands and concurrency

If the script value is an array of commands, the commands are executed serially.

    - deno run one.ts
    - deno run two.ts
  test: # Compound scripts can contain script objects as well
    - deno test test_one.ts
    - cmd: deno test test_two.ts
      tsconfig: tsconfig.json

To declare concurrent commands, list them in the pll property of an object.

      - deno run one.ts
      - deno run two.ts

Parallel and serial scripts can be combined as well.

    - pll:
        - deno run one.ts
        - deno run two.ts
    - deno run three.ts

Multiple commands specified in this way are executed separately. If you need to use pipes/redirections you can use your shell's syntax:

  start: cat file.ts | deno

Script file model

See ScriptConfiguration for a detailed description of the structure of script files.

Listing scripts


$ vr

to see a list of available scripts.

Running scripts

To run a script, use the run subcommand


or, more concisely

Arg or option Description
SCRIPT The identifier of the script to run.
ADDITIONAL ARGS Any other argument, passed to the script. Unlike npm run, the -- separator is not needed.

For example, run

$ vr start
# or
$ vr run start

to execute the start script.

If you enabled shell completions, trigger the autocomplete on one of this commands to get the available scripts as suggestions.

Exporting scripts

If you want to use velociraptor to manage your scripts, but you want to be able to execute them in environments where you can't (or don't want to) install vr, the export subcommand may be of help: it allows you to export one or more scripts as standalone executable shell files together with their env variables, Deno cli options etc.:

$ vr export [SCRIPTS]...
Arg or option Description
SCRIPTS A space-separated list of scripts to export. If omitted, all the declared scripts are exported.
-o, --out-dir The directory where the scripts will be exported (default: bin).

For example, run

$ vr export start

to export the start script. Now you can execute it by running

$ ./bin/start [ARGS]...

Scripts exporting currently only supports sh.

Shell scripting

Like in npm scripts, vr commands are executed inside a shell. The shell is determined by the SHELL env variable on Unix-like systems and by ComSpec on Windows, with respectively sh and cmd.exe as fallback values. To customize the shell without changing your default shell env variables you can use the VR_SHELL variable (a full path is required).

The shell requirements are pretty much the same as node's.

Current working directory

Velociraptor searches for script files up the folder tree starting from the directory where the vr command was launched. Scripts are run from the directory where the script file is, independently of the initial location.

Shell completions

To enable shell tab-completion for velociraptor commands, add the corresponding line to your shell's config:

  • zsh: ~/.zshrc

    source <(vr completions zsh)
  • bash: ~/.bashrc

    source <(vr completions bash)
  • fish: ~/.config/fish/

    source (vr completions fish | psub)

Editor support


Velociraptor support for VSCode adds code assistance for script configuration files (both yaml and json).


If you need any help feel free to ask in the chat or on StackOverflow using the velociraptor tag.


Show your collaborators/users you use velociraptor:

[![vr scripts](](

vr scripts

Known limitations

Commands with quotes are currently unusable when the shell is cmd.exe due to the way Rust's std::Command (used by escapes cli arguments (see here). As a workaround you can tell Velociraptor to use PowerShell instead of cmd (see Shell scripting) or run your scripts in the Windows Subsystem for Linux.

Upcoming features

  • Self-update: run vr upgrade to install the latest version.
  • Husky style git hooks: use the hook property to link a script to a git hook.

Download Details:

Author: umbopepato

Source Code:

deno nodejs node javascript

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