simple-in-memory-queue/dist/logic/queue/createQueue.js

A simple in-memory queue, for nodejs and the browser, with consumers for common usecases.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.createQueue = void 0;
const event_stream_pubsub_1 = require("event-stream-pubsub");
const split_1 = require("./split");
const castOptionalStartEndToSlice = (start, end) => end !== undefined && start !== undefined
    ? { start, end }
    : start
        ? { start: 0, end: start }
        : { start: 0, end: 1 };
const createQueue = ({ order }) => {
    // instantiate the in memory data store
    let data = [];
    // instantiate the event streams
    const on = {
        push: new event_stream_pubsub_1.EventStream(),
        peek: new event_stream_pubsub_1.EventStream(),
        pop: new event_stream_pubsub_1.EventStream(),
    };
    // define the methods for interacting with the data store
    return {
        push: (item) => {
            const items = Array.isArray(item) ? item : [item];
            data.push(...items);
            on.push.publish({ items });
        },
        peek: (start, end) => {
            const slice = castOptionalStartEndToSlice(start, end);
            const { selection } = (0, split_1.split)({ data, order, slice });
            on.peek.publish({ items: selection });
            return selection;
        },
        pop: (start, end) => {
            const slice = castOptionalStartEndToSlice(start, end);
            const { selection, remainder } = (0, split_1.split)({ data, order, slice });
            on.pop.publish({ items: selection });
            data = remainder; // update the data to remove the selection
            return selection;
        },
        get length() {
            return data.length;
        },
        on,
    };
};
exports.createQueue = createQueue;
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