Cycle.js 'simplified' api for chaining http request (for example)

index.js

import { of } from 'most'
import { div } from 'foo'
import { makeSubject } from 'bar'

function main (sources) {
  const request$ = makeSubject() // subject of requests, for all requests
  // const {request$, response$} = makeRequest1(sources, 'http://localhost:8080/hello')
  // const response$ = makeRequest2(sources, requests$, 'http://localhost:8080/hello')
  const req = (url, opts) => makeRequest2(sources, request$, url, opts)
  const response$ = req('http://my-api.com/hello')
    .flatMap(function (helloResult) {
      const secondaryUrl = `https://my-api.com/printers/${helloResult}`
      return req(secondaryUrl)
    })
    .flatMap(function (secondaryResult) {
      const secondaryUrl = `https://my-api.com/queueSubmit/${secondaryResult}`
      const data = {filename: 'foo.stl'}
      return req(secondaryUrl, {method: 'POST', data})
    })

  let vdom$ = response$
    .map(res => res.text) // We expect this to be "Hello World"
    .startWith('Loading...')
    .map(text => div('.container', [
      h1(text)
    ])
  )

  return {
    DOM: vdom$,
    HTTP: request$
  }
}

function makeRequest1 (sources, url, options) {
  const defaults = {
    category: 'makeRequest' + Math.random(),
    method: 'GET',
    data: undefined
  }
  options = Object.assign({}, defaults, options)
  const {category, method, data} = options
  let request$ = of({
    url, // GET method by default
    method,
    category,
    data
  })

  let response$ = sources.HTTP
    .select(category)
    .flatten()
  return {request$, response$}
}

// in this version, requests$ is a subject
function makeRequest2 (sources, request$, url, options) {
  const defaults = {
    category: 'makeRequest' + Math.random(),
    method: 'GET',
    data: undefined
  }
  options = Object.assign({}, defaults, options)
  const {category, method, data} = options
  request$.next({
    url, // GET method by default
    method,
    category,
    data
  })

  let response$ = sources.HTTP
    .select(category)
    .flatten()
  return response$
}