Faqtor build automation tool

Usage no npm install needed!

<script type="module">
  import faqtor from 'https://cdn.skypack.dev/faqtor';


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Promise-based build automation for the NodeJS ecosystem

Table of contents


Basically, the Faqtor build system consists of library named faqtor and CLI tool named fqr

npm i -D faqtor fqr

But for this tutorial it is easier to have fqr installed globally:

npm i -g fqr

Also you may install additional Faqtor plugins in order to use tools like rollup or browser-sync. They are called with prefix 'faqtor-of-' usually, like faqtor-of rollup or faqtor-of-browser-sync. Just search for the faqtor.

Project directory layout

The recommended directory layout for a Faqtor-based project is following:

├──build               # Folder containing all files related to the project building
│  ├──fqr.config.js    # Faqtor configuration file containing all information about how to build
│  ├──...
├──package.json        # The usual package description file
├──...                 # Other project files

In this case fqr will find fqr.config.js in the build directory automatically, with no additional configuration. But if you don't plan to have the build folder in your project, then the following structure will also work:


Faqtor configuration basics

File fqr.config.js is just JavaScript nodejs module. For example, this file is valid fqr.config.js:

module.exports = {
    hello: () => console.log("Hello, World!"),

Then if you type following bash command (with fqr installed globally):

fqr hello

you will see the expected output Hello, World!. But usually entries of module.exports are more complex objects, called factors. The faqtor library itself provides following functions for producing factors:

  • cmd
  • seq
  • all
  • func

Factor of cmd

The first one, cmd, executes binary:

const { cmd } = require("faqtor");

module.exports = {
    friends: cmd("echo 'Hello, friends!'"),
    world:   cmd("echo 'Hello, World!'"),

In this case commands fqr friends and fqr world will produce more complex outputs, for example:

fqr friends

TARGET:   friends
COMMAND:  /bin/echo  'Hello, friends!'
Hello, friends!
SUCCEED:  friends

Anouther feature of the cmd is that it can look for binaries in the local node_modules. For example if you have rimraf locally installed in your project then you can execute it:

const { cmd } = require("faqtor");

module.exports = {
    clean: cmd("rimraf *.o"),

Let's try it, assuming there are some .o files:

fqr clean

TARGET:   clean
COMMAND:  /usr/bin/node /home/osman/src/faqtor/readme/node_modules/.bin/rimraf *.o
SUCCEED:  clean

As you can see, cmd has properly found locally installed rimraf and executed it.

Factor of seq

Factor produced by seq can execute several factors one by one. It stops execution if some factor returns error. In other words, seq acts much like && operator of bash:

const { cmd, seq } = require("faqtor");

    clean = cmd("rimraf *.o"),
    hello = cmd("echo 'Hello, World!'");  

module.exports = {
    sequence: seq(hello, clean),

Try this configuration:

fqr sequence

TARGET:   sequence
COMMAND:  /bin/echo  'Hello, World!'
Hello, World!
COMMAND:  /usr/bin/node /home/osman/src/faqtor/readme/node_modules/.bin/rimraf *.o
SUCCEED:  sequence

Factor of all

Factor produced by all can execute several factors in "parallel" using Promise.all. See example above.

Factor of func

Finally, func can produce factor from user defined function, that may have about the following signature:

function MyFactor(argv?: string[]): Promise<Error>

Let's create the following configuration:

const { func } = require("faqtor");

const myHello = (someone) => console.log(`Привет, ${someone}!`)

module.exports = {
    hello: func(myHello),

Now try:

fqr "hello World"

TARGET:   hello
Привет, World!
SUCCEED:  hello

The difference between providing factor object and just function as entry is that factor have some convenient methods like task.

Method task

Let's modify the previous example:

const { func } = require("faqtor");

const myHello = (someone) => console.log(`Привет, ${someone}!`)

module.exports = {
    hello: func(myHello).task("greet someone"),

As you see we added call of the task method with argument "greet someone". Now we can see task description in the output:

fqr "hello World"

TARGET:   hello
TASK:     greet someone
Привет, World!
SUCCEED:  hello

It is especially convenient when you run many tasks during build process, and some of them may run silently.

Method factor

Another important feature of factor object is the method of the same name, factor. It has the following signature:

public factor(input?: Domain, output?: Domain): IFactor

where Domain is TypeScript type:

export type Domain = null | string | string[];

Domain argument may contain some glob or array of globs. In this case Faqtor system calculates the maximum of modification times of files matching the glob. Now the given factor will be executed in the case if the time calculated for input is greater then for output. More precisely, Faqtor system checks the following conditions consequently:

  • run factor if no input globs
  • return "nothing to do" if input has globs but no files
  • run factor if no output globs
  • run factor if has output globs but no files
  • run factor if modification time for input is greater then modification time for output
  • return "nothing to do" otherwise

Calling factor method with no arguments is meaningful for some factors that have their "native" input or output globs. Example of such factor is one produced by faqtor-of-uglify:

const uglify = minify("index.js", "index.min.js")
    .task("minifying 'index.js'");

Here "index.js" and "index.min.js" are used by default as input and output Domain's correspondently.

... to be continued ...

Real world examples

Faqtor build automation system is used in HyperOOP project. The most detailed example of Faqtor/fqr and plugins usage is source code of the HyperOOP homepage. Look at fqr.config.js. Other examples of Faqtor configuration files are HyperOOP library and HyperOOP Router library build configuration files. Also all our official plugins have Faqtor configuration files, but they are similar, look at this one for example.


You can install and run this example locally:

git clone https://github.com/faqtor/example faqtor-example
cd faqtor-example
npm i
npm start

Then try to change src/template.html and src/index.js: all changes will be visible in browser immediately.

Let's look at build configuration (build/fqr.config.js):

// Necessary utilities from 'faqtor' library:
const { seq, cmd, all } = require("faqtor")

// Factor produced by 'minify' will perform javascript minification:
const { minify } = require("faqtor-of-uglify");

// Factor produced by 'render' will run our HTML template:
const { render } = require("faqtor-of-handlebars");

// Factor to watch changes in files:
const { watch } = require("faqtor-of-watch");

// 'bs' can produce factors for usual browser-sync tasks, like 'reload' for example:
const bs = require("faqtor-of-browser-sync").create();

// In this block we create elementary parts of our building process:
    // create 'dist' and 'dist/js' folders if they don't exist, using 'mkdirp' command:
    makeDistFolder = cmd("mkdirp dist/js"),
    // create development version of 'index.html' using handlebars:
    devMakeIndexHtml = render("src/template.html", "src/index.html", {
            indexJS: "./index.js"
    // create production version of 'index.html' using handlebars:
    prodMakeIndexHtml = render("src/template.html", "dist/index.html", {
            indexJS: "js/index.js"
    // minify 'index.js' for production
    uglifyIndexJS = minify("src/index.js", "dist/js/index.js"),
    // reload browsers if something on page has changed
    reloadBrowserPage = bs.reload("src/index.*");

module.exports = {
    // entry 'build' to call from 'package.json/scripts': fqr build
    // 'seq' is sequence of tasks, analog of bash && operator
    build: seq(makeDistFolder, uglifyIndexJS, prodMakeIndexHtml),
    // entry 'serve' to call from 'package.json/scripts': fqr serve
    // watch for changes and reload page if necessary
    serve: seq(devMakeIndexHtml, all(
        bs.init({ server: { baseDir: "src" } }),
        watch([devMakeIndexHtml, reloadBrowserPage])
    // entry 'clean' to call from 'package.json/scripts': fqr clean
    clean: cmd("rimraf dist src/index.html")