@reggi/journey

npm i @reggi/journey

Why

journey allows you to design a functional flow, it is a reducer for functions with the goal of storing all values along the way into one big object, but sill allowing for a returnable value

const {journey} = require('@reggi/journey')

const cleanGreeting = (greeting) => (greeting === 'hi') ? 'Hello' : greeting

const helloWorld = journey((greeting, name) => [
  () => ({greeting, name}), // put greeting and name into the object to use
  ({greeting}) => ({cleanGreeting: cleanGreeting(greeting)}), // here we create a new property and return it it gets added to the object,
  ({cleanGreeting, name}) => ({message: `${cleanGreeting} ${name}`}) // here we have access to `name` and `cleanGreeting`, all we need
])

// Here we can call this function and get the entire function back

console.log(helloWorld('hi', 'Thomas')) // => {greeting: 'hi', name: 'Thomas', cleanGreeting: 'Hello', message: 'Hello Thomas'}

Now if we only wanted message to be returned, we would do this:

const {journey} = require('@reggi/journey')

const cleanGreeting = (greeting) => (greeting === 'hi') ? 'Hello' : greeting

const helloWorld = journey((greeting, name) => [
  () => ({greeting, name}), // put greeting and name into the object to use
  ({greeting}) => ({cleanGreeting: cleanGreeting(greeting)}), // here we create a new property and return it it gets added to the object,
  ({cleanGreeting, name}) => ({message: `${cleanGreeting} ${name}`}) // here we have access to `name` and `cleanGreeting`, all we need
], {return: 'message'})

// Here we can call this function and get just `message` back

console.log(helloWorld('hi', 'Thomas')) // => 'Hello Thomas'

// But journey also provides us another function, if we call `.journey` we get the entire object back again, even though we added `{return: message}`.

console.log(helloWorld.journey('hi', 'Thomas')) // => {greeting: 'hi', name: 'Thomas', cleanGreeting: 'Hello', message: 'Hello Thomas'}

As you can see all variables declared in the flow are accessable at the end of the function. This is very valuable, because nothing is lost, and everything is accessable.

Async functions work as well

const {journey} = require('@reggi/journey')
const fs = require('fs')
const util = require('util')
const fsRead = util.promisify(fs.readFile)

const cleanGreeting = async (greeting) => (greeting === 'hi') ? 'Hello' : greeting

const helloWorld = journey((greeting, name) => [
  () => ({greeting, name}), // put greeting and name into the object to use
  async ({greeting}) => ({cleanGreeting: await cleanGreeting(greeting)}), // here we create a new property and return it it gets added to the object,
  ({cleanGreeting, name}) => ({message: `${cleanGreeting} ${name}`}) // here we have access to `name` and `cleanGreeting`, all we need
])

helloWorld('hi', 'Thomas')
  .then(v => console.log(JSON.stringify(v))) // {"greeting":"hi","name":"Thomas","cleanGreeting":"Hello","message":"Hello Thomas"}
  .catch(console.log)

Options

The second paramater here is objects that change the essential flow.

hook

const {journey} = require('@reggi/journey')

const cleanGreeting = (greeting) => (greeting === 'hi') ? 'Hello' : greeting

const helloWorld = journey((greeting, name) => [
  () => ({greeting, name}), // put greeting and name into the object to use
  ({greeting}) => ({cleanGreeting: cleanGreeting(greeting)}), // here we create a new property and return it it gets added to the object,
  ({cleanGreeting, name}) => ({message: `${cleanGreeting} ${name}`}) // here we have access to `name` and `cleanGreeting`, all we need
], {hook: (acq, result) => console.log(result)})

console.log(helloWorld('hi', 'Thomas'))

// { greeting: 'hi', name: 'Thomas' }
// { cleanGreeting: 'Hello' }
// { message: 'Hello Thomas' }
// { greeting: 'hi',
//   name: 'Thomas',
//   cleanGreeting: 'Hello',
//   message: 'Hello Thomas' }

This will allow us to log each step allong the way.