simple-in-memory-queue
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A simple in-memory queue, for nodejs and the browser, with consumers for common usecases.
52 lines • 2.78 kB
JavaScript
;
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.createQueueWithDebounceConsumer = void 0;
const constants_1 = require("../../domain/constants");
const createQueue_1 = require("../queue/createQueue");
/**
* creates a queue with a consumer that consumes all items from it as soon as new items stop being added
*
* note
* - produces one call to the consumer for all pushes to the queue that occurred within the delay period of eachother
*
* usecases
* - waiting until all rapid activity stops to summarize the activity, before processing it
* - for example: scroll events, mouse movements, typing, etc
*/
const createQueueWithDebounceConsumer = ({ consumer, gap, }) => {
// create the queue
const queue = (0, createQueue_1.createQueue)({ order: constants_1.QueueOrder.FIRST_IN_FIRST_OUT });
// subscribe to the queue, calling the consumer, with debouncing
let priorTimeoutHandle = null;
queue.on.push.subscribe({
consumer: () => {
// if a timeout already exists, remove it
if (priorTimeoutHandle)
clearTimeout(priorTimeoutHandle);
// set a new timeout of 100ms to capture the screen changes
priorTimeoutHandle = setTimeout(() => __awaiter(void 0, void 0, void 0, function* () {
// define the current length of the queue
const length = queue.length + 0; // +0 to ensure its a copy, and not a reference
// grab all of the items currently from the queue, without removing them from the queue yet
const items = queue.peek(length);
// wait for the consumer to successfully process the items
yield consumer({ items });
// dequeue the items from the queue, now that they're all processed
queue.pop(length);
}), gap.milliseconds);
},
});
// return the queue
return queue;
};
exports.createQueueWithDebounceConsumer = createQueueWithDebounceConsumer;
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