hsipe

Here's Something I Prepared Earlier (via detached child-process)

Usage

I borrowed this idea by seeing how update-notifier operates.

The ideal use case is when you have a time-consuming asynchronous task (e.g. baking a cake, making an HTTP request, scanning a disk, etc), and you'd like to continue executing, even when those results are not ready yet. You assume that during a future execution of your script, you'll have access to the results of that previous run.

putInOven(options: OvenOptions, ...args: any[])

type OvenOptions = {
  bakePath: string,
  cakeName: string,
  interval?: number
}
 
type Cake = {
  lastBaked?: number,
  [id:string]: any
}

• bakePath is a path to a module that exports a BakeFunction named "bake"

• cakeName is a unique identifier for the background work, and scripts that use the same results can share this

• interval is the milliseconds to wait after a successful baking, to throttle your time-consuming task (default = 1 day)

type BakeFunction = (...args: any[]) => Promise<Cake>
type BakeOptions = {
  cake: Cake
}

• your BakeFunction has access to the previous Cake, which could be useful for more-efficient / partial baking

• your BakeFunction resolves with your Cake, and we automatically set "lastBaked" value in the Cake for you (used when checking interval)

getCake(options: CakeOptions) => Cake

type CakeOptions = {
  cakeName: string
}

• cakeName must be the same cake that you putInOven() earlier

• returns your Cake if it's ready (you'll have to check)

Example

index.js / cli.js (your entry-point):

const path = require('path')
 
const Conf = require('conf')
const { getCake, putInOven } = require('hsipe')
 
const cakeName = 'strawberry-shortcake'
 
// start baking our strawberry-shortcake
putInOven({ bakePath: path.join(__dirname, 'bake.js'), cakeName })
 
// try to continue on, in case we already started baking last time
const cake = getCake({ cakeName })
const flavour = cake.flavour
 
if (flavour) {
  // yay, we must have prepared something earlier
  // TODO: eat cake, enjoy flavour
} else {
  // ah, this must be our first time through here
  // better luck next time!
  // TODO: do something that doesn't require eating delicious cake
}

bake.js:

function bake ({ cake }, ...args) {
  // e.g. something that can take a while to finish
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve({ flavour: 'delicious' })
    }, 5e3)
  })
}
 
module.exports = { bake }

Contributing

Development

npm install --global flow-typed
npm install
flow-typed install
npm test

See Also

• conf

• update-notifier