VehicleMonitor-WEB/node_modules/runjs

runjs

Minimalistic building tool

• Get started
• Why runjs ?
• Features
  • Executing shell commands
  • Handling arguments
  • Documenting tasks
  • Namespacing
  • Sharing tasks
  • Autocompletion
• Transpilers
  • Babel
  • TypeScript
• API
  • run
  • options
  • help
• Using Async/Await

For 3.x to 4.x migration instructions look here

Get started

Install runjs in your project

npm install runjs --save-dev

Create runfile.js in your root project directory:

const { run } = require('runjs')

function hello(name = 'Mysterious') {
  console.log(`Hello ${name}!`)
}

function makedir() {
  run('mkdir somedir')
}

module.exports = {
  hello,
  makedir
}

Call in your terminal:

$ npx run hello Tommy
Hello Tommy!
$ npx run makedir
mkdir somedir

For node < 8.2, npx is not available, so doing npm install -g runjs-cli is neccessary which installs global run script. After that above task would be called like: run hello Tommy

Mechanism of RunJS is very simple. Tasks are run by just importing runfile.js as a normal node.js module. Then based on command line arguments proper exported function from runfile.js is called.

RunJS in a nutshell

const runfile = require(path.resolve('./runfile'))
const taskName = process.argv[2]
const { options, params } = parseArgs(process.argv.slice(2))

runfile[taskName].apply({ options }, params)

Why runjs ?

We have Grunt, Gulp, npm scripts, Makefile. Why another building tool ?

Gulp or Grunt files seem overly complex for what they do and the plugin ecosystem adds a layer of complexity towards the simple command line tools underneath. The documentation is not always up to date and the plugin does not always use the latest version of the tool. After a while customizing the process even with simple things, reconfiguring it becomes time consuming.

Npm scripts are simple but they get out of hand pretty quickly if we need more complex process which make them quite hard to read and manage.

Makefiles are simple, better for more complex processes but they depend on bash scripting. Within runfile you can use command line calls as well as JavaScript code and npm libraries which makes that approach much more flexible.

More

Features

Executing shell commands

RunJS gives an easy way to execute shell commands in your tasks by run function in synchronous and asynchronous way:

const { run } = require('runjs')

function commands () {
  run('jest')
  run(`webpack-dev-server --config webpack.config.js`, {
    async: true
  })
}

module.exports = {
  all
}

$ run commands

Because ./node_modules/.bin is included in PATH when calling shell commands by run function, you can call "bins" from your local project in the same way as in npm scripts.

Handling arguments

Provided arguments in the command line are passed to the function:

function sayHello (who) {
  console.log(`Hello ${who}!`)
}

module.exports = {
  sayHello
}

$ run sayHello world
Hello world!

You can also provide dash arguments like -a or --test. Order of them doesn't matter after task name. They will be always available by options helper from inside a function.

const { options } = require('runjs')

function sayHello (who) {
  console.log(`Hello ${who}!`)
  console.log('Given options:', options(this))
}

module.exports = {
  sayHello
}

$ run sayHello -a --test=something world
Hello world!
Given options: { a: true, test: 'something' }

Documenting tasks

To display all available tasks for your runfile.js type run in your command line without any arguments:

$ run
Processing runfile.js...

Available tasks:
echo                    - echo task description
buildjs                 - Compile JS files

Use help utility function for your task to get additional description:

const { run, help } = require('runjs')

function buildjs () {
  
}

help(buildjs, 'Compile JS files')

module.exports = {
  buildjs
}

$ run buildjs --help
Processing runfile.js...

Usage: buildjs

Compile JS files

You can provide detailed annotation to give even more info about the task:

const dedent = require('dedent')
const { run, help } = require('runjs')

function test (file) {
  
}

help(test, {
  description: 'Run unit tests',
  params: ['file'],
  options: {
    watch: 'run tests in a watch mode'
  },
  examples: dedent`
    run test dummyComponent.js
    run test dummyComponent.js --watch
  `
})

module.exports = {
  test
}

$ run test --help
Processing runfile.js...

Usage: test [options] [file]

Run unit tests

Options:

  --watch       run tests in a watch mode

Examples:

run test dummyComponent.js
run test dummyComponent.js --watch

Namespacing

To better organise tasks, it is possible to call them from namespaces:

const test = {
  unit () {
    console.log('Doing unit testing!')
  }
}

module.exports = {
  test
}

$ run test:unit
Doing unit testing!

This is especially useful if runfile.js gets too large. We can move some tasks to external modules and import them back to a namespace:

./tasks/test.js:

function unit () {
  console.log('Doing unit testing!')
}

function integration () {
  console.log('Doing unit testing!')
}

module.exports = {
  unit,
  integration
}

runfile.js

const test = require('./tasks/test')

module.exports = {
  test
}

$ run test:unit
Doing unit testing!

If we don't want to put imported tasks into a namespace, we can always use spread operator:

module.exports = {
  ...test
}

$ run unit
Doing unit testing!

With ES6 modules import/export syntax this becomes even simpler:

// export with no namespace
export * from './tasks/test' // no namespace

// export with namespace
import * as test from './tasks/test'
export { test } // add namespace

$ run unit
$ run test:unit

Sharing tasks

Because runfile.js is just a node.js module and runjs just calls exported functions from that module based on cli arguments, nothing stops you to move some repetitive tasks across your projects to external npm package and just reuse it.

shared-runfile module:

function shared1 () {
  console.log('This task is shared!')
}

function shared2 () {
  console.log('This task is shared!')
}

module.exports = {
  shared1,
  shared2
}

Local runfile.js

const shared = require('shared-runfile')

function local () {
  console.log('This task is local!')
}

module.exports = {
  ...shared,
  local
}

$ run shared1
$ run shared2
$ run local

Autocompletion

After setting up autocompletion, suggestions about available tasks from your runfile.js will be given when calling run <tab>.

This is an experimental feature. It will work slowly if you use transpiler with your runfile.js. It won't work also with npx run <task> calls, npm -g install runjs-cli is necessary, so you could do calls like run <task>.

Setup process:

1. run --completion >> ~/runjs.completion.sh
2. echo 'source ~/runjs.completion.sh' >> .bash_profile
3. Restart your shell (reopen terminal)

Depending on your shell, use proper bootstrap files accordingly.

If you get errors like _get_comp_words_by_ref command not found you need to install bash completion package. For MacOS users doing brew install bash-completion should do the job and then adding [ -f /usr/local/etc/bash_completion ] && ./usr/local/etc/bash_completion. to your ~/.bash_profile.

Transpilers

Transpilers gives you an advantage of using ES6/ES7 features which may not be available in your node version.

So for example writing runfile.js with es6 imports/exports is possible:

import { run } from 'runjs'

export function makeThatDir(name) {
  run(`mkdir ${name}`)
  console.log('Done!')
}

$ run makeThatDir somedir
mkdir somedir
Done!

Babel

If you want to use Babel transpiler for your runfile.js install it:

npm install babel-core babel-preset-es2015 babel-register --save-dev

and in your package.json write:

{
  "babel": {
    "presets": ["es2015"]
  },
  "runjs": {
    "requires": [
      "./node_modules/babel-register"
    ]
  }
}

RunJS will require defined transpiler before requiring runfile.js so you can use all ES6/ES7 features which are not supported by your node version.

TypeScript

If you want to use TypeScript transpiler for your runfile, install TypeScript tooling:

npm install typescript ts-node --save-dev

and then in your package.json define a path to ts-node/register and runfile.ts.

{
  "runjs": {
    "requires": [
      "./node_modules/ts-node/register"
    ],
    "runfile": "./runfile.ts"
  }
}

You need to also define custom path to your runfile as TypeScript files have *.ts extension. RunJS will require defined transpiler before requiring ./runfile.ts.

API

For inside runfile.js usage.

run(cmd, options)

run given command as a child process and log the call in the output. ./node_modules/.bin/ is included into PATH so you can call installed scripts directly.

const { run } = require('runjs')

Options:

{
    cwd: ..., // current working directory (String)
    async: ... // run command asynchronously (true/false), false by default
    stdio: ... // 'inherit' (default), 'pipe' or 'ignore'
    env: ... // environment key-value pairs (Object)
    timeout: ...
}

Examples:

To get an output from run function we need to set stdio option to pipe otherwise output will be null:

const output = run('ls -la', {stdio: 'pipe'})
run('http-server .', {async: true, stdio: 'pipe'}).then((output) => {
  log(output) 
}).catch((error) => {
  throw error
})

For stdio: 'pipe' outputs are returned but not forwarded to the parent process thus not printed out to the terminal.

For stdio: 'inherit' (default) outputs are passed to the terminal, but run function will resolve (async) / return (sync) null.

For stdio: 'ignore' nothing will be returned or printed

options(this)

A helper which returns an object with options which were given through dash params of command line script.

const { options } = require('runjs')

Example:

$ run lint --fix

function lint (path = '.') {
  options(this).fix ? run(`eslint ${path} --fix`) : run(`eslint ${path}`) 
}

To execute a task in JS with options:

lint.call({ options: { fix: true }}, './component.js')

help(func, annotation)

Define help annotation for task function, so it will be printed out when calling task with --help option and when calling run without any arguments.

const { help } = require('runjs')

help(build, 'Generate JS bundle')

help(test, {
  description: 'Run unit tests',
  params: ['file'],
  options: {
    watch: 'run tests in a watch mode'
  },
  examples: `
    run test dummyComponent.js
    run test dummyComponent.js --watch
  `
})

$ run build --help
$ run test --help

Using Async/Await

For node >= 7.10 it is possible to use async functions out of the box since node will support them natively.

Expected usage in your runfile:

const { run } = require('runjs')

async function testasyncawait () {
  await run('ls -al | cat', {async: true}).then((data) => {
    console.log('DATA', data)
  })
  console.log('After AWAIT message')
}

module.exports = {
  testasyncawait
}

and then just

$ run testasyncawait

If your node version is older you need to depend on transpilers, either Babel or TypeScript. For TypeScript you do no more than transpiler setup which was described above and async/await should just work.

For Babel you additionally need babel-preset-es2017 and babel-polyfill:

npm install babel-preset-es2017 babel-polyfill --save-dev

and proper config in your package.json:

"babel": {
  "presets": ["es2017"]
},
"runjs": {
  "requires": [
    "./node_modules/babel-polyfill",
    "./node_modules/babel-register"
  ]
}