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npm run enhanced.

  • Compatible with npm run for npm scripts
  • Run them concurrently or serially
  • Extend them with JavaScript
  • Group them with namespace
  • and more

Running npm scripts

This module provides a command xrun to run all your npm scripts in package.json.

And you can run multiple of them concurrently or serially.

Some examples below:

what you want to do npm command xrun command
run test npm run test xrun test
run lint and test concurrently N/A xrun lint test
run lint and then test serially N/A xrun --serial lint test

Alias for the options:

  • -s: --serial

Running JavaScript tasks

You can write your tasks in JavaScript and run them with xrun.

This is useful when a shell script is too long to fit in a JSON string, or when it's not easy to do something with shell script.

These APIs are provided: concurrent, serial, exec, env, and load.

Put your tasks in a file xrun-tasks.js and xrun will load it automatically.

An example xrun-tasks.js:

const { load, exec, concurrent, serial } = require("@xarc/run");
  // define a task hello, with a string definition
  // because a string is the task's direct value, it will be executed as a shell command.
  hello: "echo hello",
  // define a task world, using a JavaScript function to print something
  world: () => console.log("world"),
  // define a task serialTask, that will execute the three tasks serially, first two are
  // the hello and world tasks defined above, and 3rd one is a shell command defined with exec.
  // because the 3rd one is not a direct value of a task, it has to use exec to define a shell command.
  serialTask: serial("hello", "world", exec("echo hi from exec")),
  // define a task concurrentTask, that will execute the three tasks concurrently
  concurrentTask: concurrent("hello", "world", exec("echo hi from exec")),
  // define a task nesting, that does complex nesting of concurrent/serial constructs
  nesting: concurrent(serial("hello", "world"), serial("serialTask", concurrent("hello", "world")))

To run the tasks defined above from the command prompt, below are some examples:

what you want to do command
run hello xrun hello
run hello and world concurrently xrun hello world
run hello and then world serially xrun --serial hello world

exec and shell scripts

Use exec to invoke a shell command from JavaScript.

Here are some examples:

shell script in JSON string shell script using exec in JavaScript note
echo hello exec("echo hello")
FOO=bar echo hello $FOO exec("FOO=bar echo hello $FOO")
echo hello && echo world exec("echo hello && echo world")
echo hello && echo world serial(exec("echo hello"), exec("echo world")) using serial instead of &&
  • exec supports options that can set a few things. Some examples below:
what you want to do shell script using exec in JavaScript
setting an env variable exec("echo hello $FOO", {env: {FOO: "bar"}})
provide tty to the shell process exec("echo hello", {flags: "tty"})
using spawn with tty, and setting env exec("echo hello $FOO", {flags: "tty,spawn", env: {FOO: "bar"}})

Function tasks

A task in JavaScript can be just a function.

  hello: () => console.log("hello")

A function task can do a few things:

  • Return a promise or be an async function, and xrun will wait for the Promise.
  • Return a stream and xrun will wait for the stream to end.
  • Return another task for xrun to execute further.
  • Access arguments with context.argOpts.


  // A function task named hello that access arguments with `context.argOpts`
  async hello(context) {
    console.log("hello argOpts:", context.argOpts);
    return ["foo"];
  h2: ["hello world"],
  foo: "echo bar"

Running tasks with concurrent and serial

Use concurrent and serial to define a task that run multiple other tasks concurrently or serially.

Some examples:

  • To do the same thing as the shell script echo hello && echo world:
serial(exec("echo hello"), exec("echo world"));
  • or concurrently:
concurrent(exec("echo hello"), exec("echo world"));
  • You can specify any valid tasks:
  exec("echo hello"),
  () => console.log("world"),
  concurrent("task1", "task2")

Tasks to set process.env

env allows you to create a task to set variables in process.env.

You use it by passing an object of env vars, like env({VAR_NAME: "var-value"})


  setEnv: serial(env({ FOO: "bar" }), () => console.log(process.env.FOO))

And to put it all together

A popular CI/CD use case is to start servers and then run tests, which can be achieved using xrun JavaScript tasks:

const { concurrent, serial, load, stop } = require("@xarc/run");
const waitOn = require("wait-on");

const waitUrl = url => waitOn({ resources: [url] });

  "start-server-and-test": concurrent(
    // start the servers concurrently
    concurrent("start-mock-server", "start-app-server"),
      // wait for servers concurrently, and then run tests
      concurrent("wait-mock-server", "wait-app-server"),
      // Finally stop servers and exit.
      // This is only needed because there are long running servers.
      () => stop()
  "start-mock-server": "mock-server",
  "start-app-server": "node lib/server",
  "wait-mock-server": () => waitUrl("http://localhost:8000"),
  "wait-app-server": () => waitUrl("http://localhost:3000"),
  "run-tests": "cypress run --headless -b chrome"

xrun adds node_modules/.bin to PATH. That's why npx is not needed to run commands like cypress that's installed in node_modules.


Not a fan of full API names like concurrent, serial, exec? You can skip them.

  • concurrent: Any array of tasks are concurrent, except when they are specified at the top level.
  • exec: Any string starting with ~$ are treated as shell script.
  • serial: An array of tasks specified at the top level is executed serially.


  executeSerially: ["task1", "task2"], // top level array serially
  concurrentArray: [["task1", "task2"]], // Any other array (the one within) are concurrent
  topLevelShell: "echo hello", // top level string is a shell script
  shellScripts: [
    "~$echo hello", // any string started with ~$ is shell script
    "~(tty,spawn)$echo hello" // also possible to specify tty and spawn flag between ~ and $

Full List of Features

  • Support namespaces for tasks.
  • Load and execute npm scripts from package.json.
  • Auto completion for bash and zsh.
  • Define tasks in a JavaScript file.
  • Serial tasks execution.
  • Concurrent tasks execution.
  • Proper nesting task execution hierarchy.
  • Promise, node.js stream, or callback support for tasks written in JavaScript.
  • Run time flow control - return further tasks to execute from JS task function.
  • Support custom task execution reporter.
  • Specify complex tasks execution pattern from command line.
  • Tasks can have a finally hook that always runs after task finish or fail.
  • Support flexible function task that can return more tasks to run.

Getting Started

Still reading? Maybe you want to take it for a test drive?

A Simple Example

Here is a simple sample.

  1. First setup the directory and project:
mkdir xrun-test
cd xrun-test
npm init --yes
npm install rimraf @xarc/run
  1. Save the following code to xrun-tasks.js:
"use strict";
const { load } = require("@xarc/run");

const tasks = {
  hello: "echo hello world", // a shell command to be exec'ed
  jsFunc() {
    console.log("JS hello world");
  both: ["hello", "jsFun"] // execute the two tasks serially

// Load the tasks into @xarc/run
  1. And try one of these commands:
what to do command
run the task hello xrun hello
run the task jsFunc xrun jsFunc
run the task both xrun both
run hello and jsFunc concurrently xrun hello jsFunc
run hello and jsFunc serially xrun --serial hello jsFunc

A More Complex Example

Here is a more complex example to showcase a few more features:

"use strict";

const util = require("util");
const { exec, concurrent, serial, env, load } = require("@xarc/run");
const rimraf = util.promisify(require("rimraf"));

const tasks = {
  hello: "echo hello world",
  jsFunc() {
    console.log("JS hello world");
  both: {
    desc: "invoke tasks hello and jsFunc in serial order",
    // only array at top level like this is default to serial, other times
    // they are default to concurrent, or they can be marked explicitly
    // with the serial and concurrent APIs (below).
    task: ["hello", "jsFunc"]
  // invoke tasks hello and jsFunc concurrently as a simple concurrent array
  both2: concurrent("hello", "jsFunc"),
  shell: {
    desc: "Run a shell command with TTY control and set an env",
    task: exec({ cmd: "echo test", flags: "tty", env: { foo: "bar" } })
  babel: exec("babel src -D lib"),
  // serial array of two tasks, first one to set env, second to invoke the babel task.
  compile: serial(env({ BABEL_ENV: "production" }), "babel"),
  // more complex nesting serial/concurrent tasks.
  build: {
    desc: "Run production build",
    task: serial(
      () => rimraf("dist"), // cleanup, (returning a promise will be awaited)
      env({ NODE_ENV: "production" }), // set env
      concurrent("babel", exec("webpack")) // invoke babel task and run webpack concurrently


Global xrun command

If you'd like to get the command xrun globally, so you don't have to type npx xrun, you can install another small npm module @xarc/run-cli globally.

$ npm install -g @xarc/run-cli

Load and Run Tasks Programmatically

If you don't want to use the CLI, you can load and invoke tasks in your JavaScript code using the run API.


const { run, load, concurrent } = require("@xarc/run");
const myTasks = require("./tools/tasks");

// assume task1 and task2 are defined, below will run them concurrently
run(concurrent("task1", "task2"), err => {
  if (err) {
    console.log("run tasks failed", err);
  } else {
    console.log("tasks completed");

Promise version of run is asyncRun


Name your task file xrun-tasks.ts if you want to use TypeScript.

You also need to install ts-node to your node_modules


npm install -D ts-node typescript

xrun automatically loads ts-node/register when it detects xrun-tasks.ts file.

Command Line Usage

Any task can be invoked with the command xrun:

$ xrun task1 [task1 options] [<task2> ... <taskN>]


$ xrun build

For help on usage:

$ xrun -h

To load npm scripts into the npm namespace, use the --npm option:

$ xrun --npm test

You can also specify command line options under @xarc/run in your package.json.

Specifying Complex Tasks from command line

You can specify your tasks as an array from the command line.

For example, to have xrun execute the tasks [ task_a, task_b ] concurrently:

$ xrun [ task_a, task_b ]

You can also execute them serially with:

$ xrun --serial [ task_a, task_b ]

You can execute tasks serially, and then some tasks concurrently:

$ xrun --serial [task_a, task_b, [task_c1, task_c2]]

will execute task_a, then task_b, and finally task_c1 and task_c2 concurrently.

You can pass the whole array in as a single string, which will be parsed as an array with string elements only.

$ xrun "[task_a, task_b, [task_c1, task_c2]]"

Task Name

Task name is any alphanumeric string that does not contain /, or starts with ? or ~$.

Tasks can be invoked from command line:

  • xrun foo/task1 indicates to execute task1 in namespace foo
  • xrun ?task1 or xrun ?foo/task1 indicates that executing task1 is optional.

xrun treats these characters as special:

  • / as namespace separator
  • prefix ? to let you indicate that the execution of a task is optional so it won't fail if the task is not found.
  • prefix ~$ to indicate the task to be a string as a shell command

Optional Task Execution

By prefixing the task name with ? when invoking, you can indicate the execution of a task as optional so it won't fail in case the task is not found.

For example:

  • xrun ?foo/task1 or xrun ?task1 won't fail if task1 is not found.

Task Definition

A task can be string, array, function, or object. See reference for details.


You can define @xarc/run tasks and options in your package.json.


You can also define xrun tasks without JavaScript capability in your package.json.

They will be loaded into a namespace pkg.

For example:

  "name": "my-app",
  "@xarc/run": {
    "tasks": {
      "task1": "echo hello from package.json",
      "task2": "echo hello from package.json",
      "foo": ["task1", "task2"]

And you can invoke them with xrun pkg/foo, or xrun foo if there are no other namespace with a task named foo.


Command line options can also be specified under @xarc/run inside your package.json.

For example:

  "name": "my-app",
  "@xarc/run": {
    "npm": true

Async Tasks

You can provide a JS function for a task that executes asynchronously. Your function just need to take a callback or return a Promise or a node.js stream.


const tasks = {
  cb_async: (cb) => {
    setTimeout(cb, 10);
  promise_async: () => {
    return new Promise(resolve => {
      setTimeout(resolve, 10);

Detailed Reference

See reference for more detailed information on features such as load tasks into namespace, and setup auto complete with namespace for your shell.


Licensed under the Apache License, Version 2.0

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