make-mutex.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.makeKeyedMutex = exports.makeMutex = void 0;
const makeMutex = () => {
    let task = Promise.resolve();
    return {
        mutex(code) {
            task = (async () => {
                // wait for the previous task to complete
                // if there is an error, we swallow so as to not block the queue
                try {
                    await task;
                }
                catch (_a) { }
                // execute the current task
                return code();
            })();
            // we replace the existing task, appending the new piece of execution to it
            // so the next task will have to wait for this one to finish
            return task;
        },
    };
};
exports.makeMutex = makeMutex;
const makeKeyedMutex = () => {
    const map = {};
    return {
        mutex(key, task) {
            if (!map[key]) {
                map[key] = (0, exports.makeMutex)();
            }
            return map[key].mutex(task);
        }
    };
};
exports.makeKeyedMutex = makeKeyedMutex;