instrumenting code on the fly

[ORESoftware]

say we have an Express server:

app.use(function(req,res,next){
    const k = cp.spawn('istanbul instrument');
    fs.createReadStream('foo.js').pipe(k.stdin).pipe(res);
});

is there a way to instrument a file like this on the fly, and serve it to the browser?

[ORESoftware]

I asked a question on SO about this too: https://stackoverflow.com/questions/47880168/instrumenting-files-on-the-fly-with-istanbul

[ORESoftware]

I realize this is possible just by doing this:

app.use(function(req,res,next){
    const k = cp.spawn('istanbul instrument foo.js');
    k.stdout.pipe(res);
});