# Multithreading | Functional JavaScript To Speedup Heavy Workloads **URL:** \ **Category:** Tools & Scripts\ **Tags:** programming\ **Created:** [August 16, 2024, 7:23pm UTC](https://onehack.st/t/multithreading-functional-javascript-to-speedup-heavy-workloads/289125 "2024-08-16T19:23:46Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![Prometheus](https://onehack.st/user_avatar/onehack.st/prometheus/32/34950_2.png) [@Prometheus](https://onehack.st/u/Prometheus)\ **Post date:** [August 16, 2024, 7:23pm UTC](https://onehack.st/t/multithreading-functional-javascript-to-speedup-heavy-workloads/289125/1 "2024-08-16T19:23:47Z")
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It is designed to be as simple and fast as possible, and to be used in a similar way to regular functions. With a minified size of only 4.5kb, it has first class support for [Node.js](https://nodejs.org/), [Deno](https://deno.com/) and the [browser](https://caniuse.com/?search=webworkers). It can also be used with any framework or library such as [React](https://react.dev/), [Vue](https://vuejs.org/) or [Svelte](https://svelte.dev/). Depending on the environment, it uses [Worker Threads](https://nodejs.org/api/worker_threads.html) or [Web Workers](https://developer.mozilla.org/en-US/docs/Web/API/Worker). In addition to [ES6 generators](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function*) to make multithreading as simple as possible. ### The State of Multithreading in JavaScript JavaScript’s single-threaded nature means that tasks are executed one after the other, leading to potential performance bottlenecks and underutilized CPU resources. While [Web Workers](https://developer.mozilla.org/en-US/docs/Web/API/Worker) and [Worker Threads](https://nodejs.org/api/worker_threads.html) offer a way to offload tasks to separate threads, managing the state and communication between these threads is often complex and error-prone. This project aims to solve these challenges by providing an intuitive Web Worker abstraction that mirrors the behavior of regular JavaScript functions. This way it feels like you’re executing a regular function, but in reality, it’s running in parallel on a separate threads. ## Installation npm install multithreading ## Usage #### Basic example import { threaded } from “multithreading”; const add = threaded(function\* (a, b) { return a + b; }); console.log(await add(5, 10)); // 15 The `add` function is executed on a separate thread, and the result is returned to the main thread when the function is done executing. Consecutive invocations will be automatically executed in parallel on separate threads. #### Example with shared state import { threaded, $claim, $unclaim } from “multithreading”; const user = { name: “john”, balance: 0, }; const add = threaded(async function\* (amount) { yield user; // Add user to dependencies await $claim(user); // Wait for write lock user.balance += amount; $unclaim(user); // Release write lock }); await Promise.all([add(5), add(10),]); console.log(user.balance); // 15 This example shows how to use a shared state across multiple threads. It introduces the concepts of claiming and unclaiming write access using `$claim` and `$unclaim`. This is to ensure that only one thread can write to a shared state at a time. > Always `$unclaim()` a shared state after use, otherwise the write lock will never be released and other threads that want to write to this state will be blocked indefinitely. The `yield` statement is used to specify external dependencies, and must be defined at the top of the function. #### Example with external functions import { threaded, $claim, $unclaim } from “multithreading”; // Some external function function add (a, b) { return a + b; } const user = { name: “john”, balance: 0, }; const addBalance = threaded(async function\* (amount) { yield user; yield add; // Add external function to dependencies await $claim(user); user.balance = add(user.balance, amount); $unclaim(user); }); await Promise.all([addBalance(5), addBalance(10),]); console.log(user.balance); // 15 In this example, the `add` function is used within the multithreaded `addBalance` function. The `yield` statement is used to declare external dependencies. You can think of it as a way to import external data, functions or even packages. As with previous examples, the shared state is managed using `$claim` and `$unclaim` to guarantee proper synchronization and prevent data conflicts. > External functions like `add` cannot have external dependencies themselves. All variables and functions used by an external function must be declared within the function itself. ### Using imports from external packages When using external modules, you can dynamically import them by using `yield "some-package"`. This is useful when you want to use other packages within a threaded function. import { threaded } from “multithreading”; const getId = threaded(function\* () { /\*\* \* @type {import(“uuid”)} \*/ const { v4 } = yield “uuid”; // Import other package return v4(); } console.log(await getId()); // 1a107623-3052-4f61-aca9-9d9388fb2d81 You can also import external modules in a variety of other ways: const { v4 } = yield “npm:uuid”; // Using npm specifier (available in Deno) const { v4 } = yield “[https://esm.sh/uuid](https://esm.sh/uuid)”; // From CDN url (available in browser and Deno) ## Enhanced Error Handling Errors inside threads are automatically injected with a pretty stack trace. This makes it easier to identify which line of your function caused the error, and in which thread the error occured. [![Example of an enhanced stack trace](https://private-user-images.githubusercontent.com/38042257/294755558-4c5b3352-ad19-4270-86e4-dad6fc6e0fe6.svg?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.tBayPtO8-Wu3H5I9zg7sqLngMkvnI5Mw72cyZTlBzBo)](https://private-user-images.githubusercontent.com/38042257/294755558-4c5b3352-ad19-4270-86e4-dad6fc6e0fe6.svg?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.tBayPtO8-Wu3H5I9zg7sqLngMkvnI5Mw72cyZTlBzBo) ## GitHub: [https://github.com/W4G1/multithreading](https://github.com/W4G1/multithreading)