promise-spin-wait

promise-spin-wait

An ES6-Promise based spin wait

Install

$ npm install --save promise-spin-wait

Usage

Imagine you'd want to test a script that sends emails. Sadly the infrastructure that actually sends them is out of your controll, so emails are not delivered instantly. This is when a spin wait can be useful, it allows you to check regularly for a certain criteria until it's fulfilled.

const spinner = require('promise-spin-wait');

return sendEmail() // Asyncronous, but it will return before the email has actually been delivered
.then(() => {
    return spinner(
        () => {
            return getEmailInboxCount().then(n => n > 0);
        },
        {
            message: "Timeout: No Email received",
            timeout: 5000,
            interval: 500
        }
    );
})

API

spinner(fn, options)

Returns a promise for a the first truish response of fn() or the first rejected promise of fn();

fn

A function returning a value or a promise. If a promise is returned fn() will not be called again until it is resolved. Any errors thrown or promise rejections will lead to the spinner rejecting as well.

Only a truish return value will lead to the spinner stopping.

options

message

Type: string
Default: Timeout

Message thrown when timeout occurs

timeout

Type: number
Default: 5000

Milliseconds since start when instead of calling fn again an timeout error will be returned

interval

Type: number
Default: 100

Duration between the last time fn() has been fulfilled and the next fn() is being called

License

MIT © marekventur