invoke a child process via fork() when using ts-node

Question

I have a typescript project and rather than using tsc first, I'm just running via ts-node directly.

In my code I need to create a child process with fork().

If I run code like child_process.fork('ChildProcess.ts') and ChildProcess.ts contains some typescript only constructs (eg: import {}, export, ...), then the interpreter being node, not ts-node, will fail.

It may be recommended to use something like child_process.exec('node ./node_modules/.bin/ts-node ChildProcess.ts), but I really want/need the IPC communication channel that gets set up between the parent and child processes when fork() specifically is used.

Any ideas on how to achieve this?

Thanks!

Answer 1

As the reference states, execArgv in forked process is inherited from current process:

execArgv List of string arguments passed to the executable. Default: process.execArgv.

When entry point runs as:

ts-node index.ts

execArgv defaults to ts-node binary:

[ '...\\ts-node\\dist\\_bin.js' ]

And

child_process.fork('ChildProcess.ts') 

runs with ts-node too.

Answer 2

If you omit the file extension when forking the process, it works with ts-node during developement, as well as with tsc and node in production.

In your app.ts file:

import { fork } from 'child_process';

fork('./longRunningProcess');

Then you can have TypeScript constructs in your longRunningProcess.ts file. After transpilation to app.js and longRunningProcess.js, it will still work when running with regular node.