delay-promise

Delay promise

A ES6 promise wrapper library to throttle and batch promises

const delayed = require('delay-promise');

// A sample promise which takes an argument
function promise(name) {
    console.log('Begin task', name);
    return new Promise(function(resolve, reject) {
        setTimeout(function() {
            console.log('Finish task', name);
            return resolve();
        }, 1000);
    });
};

delayed.creator creates a wrapper function the promise which allows the delaying of the promise execution

const promiseCreator = delayed.creator(promise, 'promise param');

Both delayed.series and delayed.parallel accepts an array of delayed.creator objects

Sequentially execute an array of delayed creators with the delay of 1 second between each promise

delayed.series([
    delayed.creator(promise, 'Series A'),
    delayed.creator(promise, 'Series B'),
    delayed.creator(promise, 'Series C')
], 1000).then((promisesArray) => {
    // returns an array of resolved values of the promises just like Promise.all
});

To produce a throttled or staggered effect use delayed.parallel

Parallelly execute an array of delayed creators with the delay of 1 second between each promise

delayed.parallel([
    delayed.creator(promise, 'Parallel A'),
    delayed.creator(promise, 'Parallel B'),
    delayed.creator(promise, 'Parallel C')
], 1000).then((promisesArray) => {
    // returns an array of resolved values of the promises just like Promise.all
});

Use both parallel and series for throttling and batching

const batch1 = delayed.creator(delayed.parallel, [
    delayed.creator(promise, 'batch task1'),
    delayed.creator(promise, 'batch task2'),
    delayed.creator(promise, 'batch task3')
], 1000); // 1 second delay between each parallel promise

const batch2 = delayed.creator(delayed.parallel, [
    delayed.creator(promise, 'batch task4'),
    delayed.creator(promise, 'batch task5'),
    delayed.creator(promise, 'batch task6')
], 1000); // 1 second delay between each parallel promise

// 1 second delay between each batch
delayed.series([ batch1, batch2 ], 1000).then((batchArray) => {
    // Array of batches
});