concurrency.js

npm module to work with concurrency - worker threads and worker processes easily using simple functions and script files

Installation

npm install concurrency.js --save

Find the demos in the demos folder. Works but is experimental. Use at your own risk. Please provide as much feedbacks as possible

Run tasks in async mode using promises as simple as below:

// This repository's root folder
const { runPromiseTasks } = require("concurrency.js") // require("../tasks.async.js");

// --- Execution Plan using String Names ---
const executionPlan = [
    "taskone",                       // Index 0
    ["tasktwo", "taskthree", "taskone"], // Index 1 (Parallel)
    "taskfour",                      // Index 2
    "taskthree",                     // Index 3
    "taskone"                        // Index 4
];

const resultContext = {};
// This repository's demos folder
const taskLibraryPath = './demos/libmap.js';

runPromiseTasks(executionPlan, resultContext, taskLibraryPath)
    .then((finalContext) => {
        console.log("\n--- Promises Based Final Accumulated Results Context ---");
        console.log(JSON.stringify(finalContext, null, 2));
    })
    .catch((err) => {
        console.error("Task execution failed:", err);
    });

Run tasks in a mix of nodejs code and run threaded code of nodejs execution plan

// This repository's root folder
const {runThreadedTasks, createWorkerPool} = require("concurrency.js")  // require("../tasks.thread")

// --- Execution Plan ---
const executionPlan = [
  "taskone",
  ["tasktwo", "taskthree", "taskone"], // Threaded parallel
  "taskfour",
  "taskthree",
  "taskone"
];

const resultContext = { results: [] };
// This repository's demos folder
const taskFileName = './demos/libmap.js'; 

// The file to be imported dynamically
//      from concurrent-tasks\worker.js

runThreadedTasks(executionPlan, resultContext, taskFileName)
  .then(final => {
    console.log("\n--- Threads Based Final Accumulated Results ---");
    console.log(JSON.stringify(final, null, 2));
    process.exit(0);
  })
  .catch(err => {
    console.error("Fatal Error:", err);
    process.exit(1);
  });

Run tasks in a mix of nodejs code and run process worker code of nodejs execution plan

// This repository's root folder
const { runProcessTasks, runInProcess }  = require("concurrency.js")  // require("../tasks.process");

// --- Execution Plan ---
const executionPlan = [
  "taskone",                       // Index 0
  ["tasktwo", "taskthree", "taskone"], // Index 1 (Parallel Processes)
  "taskfour",                      // Index 2
  "taskthree",                     // Index 3
  "taskone"                        // Index 4
];

const resultContext = { results: [] };
const taskLibraryPath = './demos/libmap.js';
// This repository's demos folder

runProcessTasks(executionPlan, resultContext, taskLibraryPath)
  .then(final => {
    console.log("\n--- Final Accumulated Results (Process-Based) ---");
    console.log(JSON.stringify(final, null, 2));
  })
  .catch(err => {
    console.error("Execution Error:", err);
  });

Contributions

Contributions, Feature Improvements, Bugs, and Issues are invited. raising an issue

TODO

Todo

License

MIT License