@byungi/p-while

A promise for an asynchronous while loop.

Example

import pWhile from '@byungi/p-while'

let tries = 0

const loopPromise = pWhile(
    async () => {
        return (await asyncAlwaysTrue()) && (++tries < 10)
    },
    async () => {
        const jobResult = await asyncJob()

        if(!jobResult) loopPromise.break() // Stop the asynchronous loop.

        return jobResult
    }
)

loopPromise.then(lastJobResult => {
    // Get the last return value.
    // If the action function has never been called, It is undefined.
})

API

pWhile(condition, action[, options])

A promise for an asynchronous while loop.

options

• interval - Delay before the next loop. Default is 0.

promise.break()

Stop the loop and resolve the promise.

promise.cancel([reason])

Do not retry anymore and throw a CancelError.

import pWhile, {CancelError} from '@byungi/p-while'

const loopPromise = pWhile(true, asyncJobInLoop)

setTimeout(()=> loopPromise.cancel(), 100) // After 100ms, the loop stops.

loopPromise.catch(err => {
    console.log(err.isCanceled) // => true
    console.log(err instanceof CancelError) // => true
    console.log(loopPromise.isCanceled) // => true
})

promise.isCanceled

Returns whether the promise is canceled.

promise.pipe(onFulfilled, onRejected)

Similar to then but can propagate cancel to the upper promise.

const handleWithLoopPromise = loopPromise.pipe(result => {
    handleLoopResult(result)
})

handleWithLoopPromise.cancel() // => The loop stops.

License

MIT