barro/lib/watchBarrelFiles.js

Flexible barrel file generation for Javascript and Typescript with watching built-in.

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.watchBarrelFiles = void 0;
const chokidar_1 = __importDefault(require("chokidar"));
const getBarrelIgnoreGlobs_1 = require("./getBarrelIgnoreGlobs");
let eventIdCounter = 1;
function watchBarrelFiles(barrel, onChange) {
    let watchCancelled = false;
    let currentEventId = 0; // Used to determine if a watch event is stale and should cancel writing
    let queue = Promise.resolve(); // Promise queue to avoid compiling the same index multiple times concurrently
    const watcher = chokidar_1.default.watch(barrel.match, {
        cwd: barrel.matchDirectory,
        ignored: getBarrelIgnoreGlobs_1.getBarrelIgnoreGlobs(barrel),
        ignoreInitial: true,
    });
    // Wait until all previous calls have run before running again
    const handleWatchEvent = async (eventType, filepath) => {
        const eventId = (currentEventId = eventIdCounter);
        eventIdCounter += 1;
        // if another event was received before this one finishes, allow `onChange` to react accordingly
        const isCancelled = () => watchCancelled || currentEventId !== eventId;
        const nextInQueue = async () => onChange(eventType, filepath, isCancelled);
        queue = queue.then(nextInQueue, nextInQueue);
        await queue;
    };
    // Watch event listeners
    const onAddFile = async (path) => handleWatchEvent("add", path);
    const onUnlinkFile = async (path) => handleWatchEvent("unlink", path);
    const onUnlinkDir = async (path) => handleWatchEvent("unlinkDir", path);
    const teardown = () => {
        watchCancelled = true;
        watcher.off("add", onAddFile);
        watcher.off("unlink", onUnlinkFile);
        watcher.off("unlinkDir", onUnlinkDir);
    };
    watcher.on("add", onAddFile);
    watcher.on("unlink", onUnlinkFile);
    watcher.on("unlinkDir", onUnlinkDir);
    return teardown;
}
exports.watchBarrelFiles = watchBarrelFiles;
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