Create a promise that reports progress
Useful for reporting progress to the user during long-running async operations.
$ npm install p-progress
const PProgress = require('p-progress');
(async () => {
const progressPromise = new PProgress((resolve, reject, progress) => {
const job = new Job();
job.on('data', data => {
progress(data.length / job.totalSize);
});
job.on('finish', resolve);
job.on('error', reject);
});
progressPromise.onProgress(progress => {
console.log(`${progress * 100}%`);
//=> 9%
//=> 23%
//=> 59%
//=> 75%
//=> 100%
});
await progressPromise;
})();Same as the Promise constructor, but with an appended progress parameter in executor.
PProgress is a subclass of Promise.
Type: Function
Call this with progress updates. It expects a number between 0 and 1.
Multiple calls with the same number will result in only one onProgress()
event.
Calling with a number lower than previously will be ignored.
Progress percentage 1 is reported for you when the promise resolves. If you set it yourself, it will simply be ignored.
Type: number
The current progress percentage of the promise as a number between 0 and 1.
Accepts a function that gets instance.progress as an argument and is called for every progress event.
Convenience method to make your promise-returning or async function report progress.
The function you specify will have the progress() function appended to its parameters.
const PProgress = require('p-progress');
const runJob = PProgress.fn(async (name, progress) => {
const job = new Job(name);
job.on('data', data => {
progress(data.length / job.totalSize);
});
await job.run();
});
(async () => {
const progressPromise = runJob('Gather rainbows');
progressPromise.onProgress(console.log);
//=> 0.09
//=> 0.23
//=> 0.59
//=> 0.75
//=> 1
await progressPromise;
})();Convenience method to run multiple promises and get a total progress of all of them. It counts normal promises with progress 0 when pending and progress 1 when resolved. For PProgress type promises, it listens to their onProgress() method for more fine grained progress reporting. You can mix and match normal promises and PProgress promises.
const PProgress = require('p-progress');
const delay = require('delay');
const progressPromise = PProgress.fn(async progress => {
progress(0.14);
await delay(52);
progress(0.37);
await delay(104);
progress(0.41);
await delay(26);
progress(0.93);
await delay(55);
});
const allProgressPromise = PProgress.all([
delay(103),
progressPromise(),
delay(55),
delay(209)
]);
(async () => {
allProgressPromise.onProgress(console.log);
//=> 0.0925
//=> 0.3425
//=> 0.5925
//=> 0.6025
//=> 0.7325
//=> 0.9825
//=> 1
await allProgressPromise;
})();Type: Promise[]
Array of promises or promise-returning functions, similar to p-all.
Type: object
Type: number
Default: Infinity
Minimum: 1
Number of concurrently pending promises.
To run the promises in series, set it to 1.
When this option is set, the first argument must be an array of promise-returning functions.
- p-cancelable - Create a promise that can be canceled
- More…