async-argument-reducer

async-argument-reducer

This package allows you to wrap a function so that it can be called several times but the execution will be delayed for some number of milliseconds (0 by default) so as to aggregate arguments across calls. It's a bit like throttling or debouncing, except that you wind up with all of the arguments from each call.

The wrapper function returns a promise which resolves to the result of invoking your callback with the aggregated set of arguments. Each set of aggregated calls gets its own promise.

Installation

npm install async-argument-reducer

Usage

const wait = require('async-argument-reducer');

const loggerOne = wait(console.log);

loggerOne(1);
loggerOne(2);
loggerOne(3, 4);

setTimeout(() => {
    loggerOne('a');
    loggerOne('b');
    loggerOne('c', 'd');
}, 0);

// =>
// [[1], [2], [3, 4]]
// [['a'], ['b'], ['c', 'd']]

As seen here, by default the arguments from each call are gathered up into an array and pushed onto a collecting array for the group of calls as a whole. You will probably want to specify some kind of aggregation for these arguments. In that case provide your own reducing function as the second paramater. For example:

const loggerTwo = collector(console.log, (args) => Array.prototype.concat(...args))

loggerTwo(1, 2);
loggerTwo(3, 4);
loggerTwo(5, 6);

// =>
// [1, 2, 3, 4, 5, 6]

You can also specify, as a third parameter, the number of milliseconds over which to aggregate arguments. By default this is 0 (i.e., just wait until the next tick).

const loggerThree = collector(console.log, null, 10);

License

ISC.