@ipp/cli/dist/lib/stream/operators/buffer.js

An image build orchestrator for the modern web

"use strict";
/**
 * Image Processing Pipeline - Copyright (c) Marcus Cemes
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.buffer = void 0;
const denque_1 = __importDefault(require("denque"));
const events_1 = require("events");
const object_stream_1 = require("../object_stream");
function buffer(count) {
    return (source) => (0, object_stream_1.createObjectStream)((async function* () {
        let ended = false;
        const events = new events_1.EventEmitter();
        const queue = new denque_1.default();
        // Ready the source asynchronously and fill the buffer
        (async function () {
            for await (const item of source) {
                while (buffer.length === count) {
                    await (0, events_1.once)(events, "item");
                }
                queue.push(item);
                events.emit("item");
            }
            ended = true;
            events.emit("item");
        })();
        // Yield items from the buffer
        while (!queue.isEmpty() || !ended) {
            if (queue.isEmpty()) {
                await (0, events_1.once)(events, "item");
            }
            while (!queue.isEmpty()) {
                yield queue.shift();
            }
        }
    })());
}
exports.buffer = buffer;