How to create threads in nodejs

Question

Is there any way to create threads for running multiple methods at a time    That way  if any method fails in between all the other threads should be killed

User · Answer

I needed real multithreading in Node js and what worked for me was the threads package  It spawns another process having it s own Node js message loop  so they don t block each other  The setup is easy and the documentation get s you up and running fast  Your main program and the workers can communicate in both ways and worker  threads  can be killed if needed   Since multithreading and Node js is a complicated and widely discussed topic it was quite difficult to find a package that works for my specific requirement  For the record these did not work for me    tiny-worker allowed spawning workers  but they seemed to share the same message loop  but it might be I did something wrong - threads had more documentation giving me confidence it really used multiple processes  so I kept going until it worked  webworker-threads didn t allow require-ing modules in workers which I needed   And for those asking why I needed real multi-threading  For an application involving the Raspberry Pi and interrupts  One thread is handling those interrupts and another takes care of storing the data  and more

User · Answer

Every node js process is single threaded by design   Therefore to get multiple threads  you have to have multiple processes  As some other posters have pointed out  there are also libraries you can link to that will give you the ability to work with threads in Node  but no such capability exists without those libraries   See answer by Shawn Vincent referencing https   github com audreyt node-webworker-threads     You can start child processes from your main process as shown here in the node js documentation   http   nodejs org api child process html   The examples are pretty good on this page and are pretty straight forward   Your parent process can then watch for the close event on any process it started and then could force close the other processes you started to achieve the type of one fail all stop strategy you are talking about   Also see   Node js on multi-core machines

User · Answer

If you re using Rx  it s rather simple to plugin in rxjs-cluster to split work into parallel execution    disclaimer  I m the author   https   www npmjs com package rxjs-cluster

User · Answer

The nodejs 10 5 0 release has announced multithreading in Node js  The feature is still experimental  There is a new worker threads module available now   You can start using worker threads if you run Node js v10 5 0 or higher  but this is an experimental API  It is not available by default  you need to enable it by using  --experimental-worker when invoking Node js   Here is an example with ES6 and worker threads enabled  tested on version 12 3 1    package json     scripts        start    node  --experimental-modules --experimental- worker index mjs         Now  you need to import Worker from worker threads   Note  You need to declare you js files with   mjs  extension for ES6 support     index mjs import   Worker   from  worker threads    const spawnWorker   workerData   gt        return new Promise  resolve  reject    gt            const worker   new Worker    workerService mjs     workerData             worker on  message   resolve           worker on  error   reject           worker on  exit   code   gt  code     0  amp  amp  reject new Error  Worker stopped with          exit code   code                 const spawnWorkers        gt        for  let t   1  t  lt   5  t            spawnWorker  Hello   then data   gt  console log data       spawnWorkers      Finally  we create a workerService mjs    workerService mjs import   workerData  parentPort  threadId   from  worker threads       You can do any cpu intensive tasks here  in a synchronous way    without blocking the  main thread  parentPort postMessage    workerData  from worker   threadId       Output      npm run start   Hello from worker 4 Hello from worker 3 Hello from worker 1 Hello from worker 2 Hello from worker 5

User · Answer

You can get multi-threading using Napa js    https   github com Microsoft napajs   Napa js is a multi-threaded JavaScript runtime built on V8  which was originally designed to develop highly iterative services with non-compromised performance in Bing  As it evolves  we find it useful to complement Node js in CPU-bound tasks  with the capability of executing JavaScript in multiple V8 isolates and communicating between them  Napa js is exposed as a Node js module  while it can also be embedded in a host process without Node js dependency

User · Answer

From Node 10 5 there is now multi threading support  but it is experimental  Hope this will become stable soon    Checkout following resources     PR thread    Official Documentation   Blog article  Threads in Node 10 5 0  a practical intro     Update   From Node v11 7 0 onward  you do not have to use --experimental-worker flag   Release note  https   nodejs org en blog release v11 7 0

User · Answer

Node js doesn t use threading  According to its inventor that s a key feature  At the time of its invention  threads were slow  problematic  and difficult  Node js was created as the result of an investigation into an efficient single-core alternative  Most Node js enthusiasts still cite ye olde argument as if threads haven t been improved over the past 50 years   As you know  Node js is used to run JavaScript  The JavaScript language has also developed over the years  It now has ways of using multiple cores - i e  what Threads do  So  via advancements in JavaScript  you can do some multi-core multi-tasking in your applications  user158 points out that Node js is playing with it a bit  I don t know anything about that  But why wait for Node js to approve of what JavaScript has to offer    Google for JavaScript multi-threading instead of Node js multi-threading  You ll find out about Web Workers  Promises  and other things

User · Answer

You might be looking for Promise race  native I O racing solution  not threads   Assuming you  or others searching this question  want to race threads to avoid failure and avoid the cost of I O operations  this is a simple and native way to accomplish it  which does not use threads   Node is designed to be single threaded  look up the event loop   so avoid using threads if possible  If my assumption is correct  I recommend you use Promise race with setTimeout  example in link   With this strategy  you would race a list of promises which each try some I O operation and reject the promise if there is an error  otherwise timeout   The Promise race statement continues after the first resolution rejection  which seems to be what you want  Hope this helps someone

User · Answer

NodeJS now includes threads  as an experimental feature at time of answering

User · Answer

There is also now https   github com xk node-threads-a-gogo  though I m not sure about project status

User · Answer

There is also at least one library for doing native threading from within Node js  node-webworker-threads  https   github com audreyt node-webworker-threads  This basically implements the Web Worker browser API for node js

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