inside-out-async
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    1.0.1 • Public • Published

    Inside Out Async

    Release

    It's pretty handy for turning things that are not promises and generators into promises and generators. Good for testing, but also for having more control over how things execute.

    npm install inside-out-async

    I nerd sniped myself and made this library. defer() is easily written in any new project, deferGenerator() is not.

    Exports two functions

    API

    defer

    function defer<T>(): Deferred<T>
    
    interface Deferred<T> {
        promise: Promise<T>
        resolve: (value: T) => void
        reject: (error: Error) => void
    }

    Creates a promise and control functions. The promise is resolved and rejected by the control functions. Like the Promise constructor but inside out.

    import { defer } from 'inside-out-async'
    import { Trainer } from 'pokemon-trainer'
    
    const pokemonCaught = defer()
    const ash = new Trainer()
    ash.on('capture', pokemonCaught.resolve)
    ash.on('error', pokemonCaught.reject)
    
    const pokemon = await pokemonCaught.promise
    console.log(pokemon) // { name: 'Pikachu', temperament: 'surprised' }

    deferGenerator

    function deferGenerator<T, TReturn, TNext = unknown>(): DeferredGenerator<T, TReturn, TNext>
    
    interface DeferredGenerator<T, TReturn, TNext> {
        generator: AsyncGenerator<T, TReturn, TNext>
        queueValue: (value: T) => void
        error: (err?: any) => void
        queueError: (err?: any) => void
        return: (value?: TReturn) => void
        queueReturn: (value?: TReturn) => void
    }

    Creates an async generator and control functions. The async generator yields values, errors, and returns based on the control functions.

    • queueValue queues a value to yielded next
    • error drops all queued values, puts the generator in a "done" state, and has the current pending or next call to next() throw an error
    • queueError puts the generator in a "done" state, and has the current pending or next call to next() throw an error
    • return() drops all queued values, and puts the generator in a "done" state with the passed in value
    • queueReturn() puts the generator in a "done" state with the passed in value
    import { deferGenerator } from 'inside-out-async'
    
    const pokedex = deferGenerator()
    pokedex.queueValue({ name: 'Pikachu' })
    pokedex.queueValue({ name: 'Bulbasaur' })
    pokedex.queueValue({ name: 'Charizard' })
    pokedex.queueReturn()
    
    for await (const pokemon of pokedex.generator) {
      console.log(pokemon) // { name: 'Pikachu' }, { name: 'Bulbasaur' }, { name: 'Charizard' }
    }

    Install

    npm i inside-out-async

    DownloadsWeekly Downloads

    150

    Version

    1.0.1

    License

    MIT

    Unpacked Size

    13.9 kB

    Total Files

    6

    Last publish

    Collaborators

    • reconbot