robinpokorny

export default (tasks, {
  args = [],
  initial,
  isEmpty = (x) => !x
} = {}) =>
  tasks.reduce(
    (prev, next) => prev.then((value) =>
      isEmpty(value) ? next(...args) : value
    ),
    Promise.resolve(initial)

robinpokorny

const firstResult = (services) => { /* … */ }

firstResult([
  () => Promise.resolve([]),
  () => Promise.resolve(['Berlin']),
  () => console.error('Do not call me!')
])
  .then((result) =>
    console.assert(result[0] === 'Berlin', 'Test1 failed!')
  )

robinpokorny

// @flow

// BAD
// Will throw this type error:
// ‘undefined This type is incompatible with some incompatible instantiation of `T`’
const resolve = <T> (init?: T): Promise<T>  => Promise.resolve(init)

// GOOD
// The return promise type is `?T`, i.e. nullable T
const resolve = <T> (init?: T): Promise<?T> => Promise.resolve(init)

robinpokorny

// @flow
type Task<T> = (...args: any[]) => Promise<?T>

type Options<T> = {
  args?: any[],
  initial?: T,
  isEmpty?: (value: ?T) => boolean
}

export default <T> (

robinpokorny

👍 - +1

👎 - -1

🅰️ - a

🆎 - ab

🔤 - abc

robinpokorny

ul.menu--primary
body .menu--primary
#page.item .item--primary .item--secondary
.menu__nav--primary i.item__icon.item__icon--spinning
.menu>.item--bold
a[lang|=cs].item--bold
*:hover .item--disabled+a.item--bold:active

robinpokorny

export * as moduleA from './moduleA'

// should be a shorthand for:

import * as _moduleA from './moduleA'
export const moduleA = _moduleA

robinpokorny

// This function isolates the logic
// Its param is number `i`
// It returns 'Fizz', 'Bazz', 'FizzBuzz' or the number
// (This implementation takes advatage of some JavaScript specific features)
const toFizzBuzz = (i) =>
  // We construct a string

  // First part is 'Fizz' if the number is divisible by 3
  // and an empty string otherwise
  // `i%3` is 0 iff `i` is divisible by 3

robinpokorny

See also 📢 Dead simple tweetable JavaScript Emitter pattern module using Map (ES2015) which uses this package.

Browser compatibility (all)

Chrome*	Edge	FF	IE	Opera	Safari	iOS
38	12	13	-*	25	7.1	8

Notes:

robinpokorny

var pokemons = [
    {
      "name": "rattata",
      "resource_uri": "api/v1/pokemon/19/"
    },
    {
      "name": "charmander",
      "resource_uri": "api/v1/pokemon/4/"
    },
    {