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seriously like the best async child process library

(I'm joking, you may want to useexeca which has a lot more features. The minor advantages of this package are,it's a dual CJS/ESM package, and it provides wrappers for all the asyncchild_process functions.)

Based uponchild-process-async,but more thorough, because that package doesn't seem very actively maintained.

promisify-child-process provides adrop-in replacement for theoriginalchild_process functions, not just duplicate methods thatreturn aPromise. So when you callexec(...) we still return aChildProcess instance, just with.then(),.catch(), and.finally() added tomake it promise-friendly.

npm install --save promisify-child-process

If you are using a old version of Node without built-inPromises orObject.create, you will need to use polyfills (e.g.@babel/polyfill).

// OLD:const{ exec, spawn, fork, execFile}=require('child_process')// NEW:const{ exec, spawn, fork, execFile}=require('promisify-child-process')

You must now passmaxBuffer orencoding tospawn/fork if you want tocapturestdout orstderr.

The child process promise will only resolve if the process exits with a code of 0.If it exits with any other code, is killed by a signal, or emits an'error' event,the promise will reject.

exec andexecFile capturestdout andstderr by default. Butspawn andfork don't capturestdout andstderr unless you pass anencoding ormaxBuffer option:

const{ spawn}=require('promisify-child-process');asyncfunction(){// captures outputconst{ stdout, stderr}=awaitspawn('ls',['-al'],{encoding:'utf8'});const{ stdout, stderr}=awaitspawn('ls',['-al'],{maxBuffer:200*1024});// BUG, DOESN'T CAPTURE OUTPUT:const{ stdout, stderr}=awaitspawn('ls',['-al']);}

If the child process promise rejects, the error may have the following additionalproperties:

• code - the process' exit code (if it exited)
• signal - the signal the process was killed with (if it was killed)
• stdout - the capturedstdout (if output capturing was enabled)
• stderr - the capturedstderr (if output capturing was enabled)

If for any reason you need to wrap aChildProcess you didn't create,you can use the exportedpromisifyChildProcess function:

const{ promisifyChildProcess}=require('promisify-child-process');asyncfunction(){const{ stdout, stderr}=awaitpromisifyChildProcess(some3rdPartyFunctionThatReturnsChildProcess(),{encoding:'utf8'})}

asyncfunction(){const{ stdout, stderr}=awaitexec('ls -al');// OR:constchild=exec('ls -al',{});// do whatever you want with `child` here - it's a ChildProcess instance just// with promise-friendly `.then()` & `.catch()` functions added to it!child.stdin.write(...);child.stdout.pipe(...);child.stderr.on('data',(data)=> ...);const{ stdout, stderr}=awaitchild;}

asyncfunction(){const{ stdout, stderr, code}=awaitspawn('ls',['-al'],{encoding:'utf8'});// OR:constchild=spawn('ls',['-al'],{});// do whatever you want with `child` here - it's a ChildProcess instance just// with promise-friendly `.then()` & `.catch()` functions added to it!child.stdin.write(...);child.stdout.pipe(...);child.stderr.on('data',(data)=> ...);const{ stdout, stderr, code}=awaitchild;}