p-wait-for-value

Wait for a condition to return existy then pass that value on

Can be useful for polling for a value to show up.

Install

$ npm install --save p-wait-for-value

Usage

const pWaitFor = require('p-wait-for-value');
const pathExists = require('path-exists');
const get = require('lodash.get');
 
pWaitForValue(() => someAPI().then(body => get(body, 'some.val')))
  .then((val) => {
    console.log('Yay! The value exists on the api payload.');
})

API

pWaitForValue(condition, [options || interval])

Returns a Promise that resolves when condition returns a value that is existy (val !== null || val !== undefined). Condition is polled if condition is not existy. Rejects if condition throws or returns a Promise that rejects. Returns the first value that is found to be existy.

condition

Type: Function

Expected to return any existy value as soon as it is available. Otherwise return null or undefined.

options

interval

Type: number
Default: 20

Number of milliseconds to wait before retrying condition. You can also pass a number in place of the options object to set the interval.

timeout

Type: number
Default: Infinity

Number of milliseconds to wait before automatically rejecting.

Related

• p-whilst - Calls a function repeatedly while a condition returns true and then resolves the promise
• p-wait-for - Wait for a condition to be true or false. Useful for polling when you don't need to retrieve a value from the condition.
• More…

License

MIT © Bret Comnes