node.js - Visual Studio Code redirect input on debug

Question

My application is reading from stdin:

var input = process.stdin.read();

Is it possible to configure Visual Studio Code to redirect input on debug?

So it is be equal to this command line:

node app.js < input.txt

This configuration is not working, and debug is not starting.

{
  "name": "Launch",
  "type": "node",
  "program": "app.js",
  "stopOnEntry": false,
  "args": [
    "<",
    "input.txt"
  ]
}

Answer 1

The args array is generally for Node.js startup and V8 engine runtime flags.

  --no-deprecation
  --throw-deprecation
  --trace-deprecation
  --v8-options
  --max-stack-size=val
  --icu-data-dir=dir

  --enable-ssl2
  --enable-ssl3

Type node --v8-options at the command line to see the full list of V8 runtime flags.

I'd recommend you start your application with the debug flag from the command line so you can direct it to take stdin and then attach the debugger to your running process.

> node --debug app.js
Debugger listening on port 5858

You can have multiple configurations in your launch.json file. Add or modify one to be your "Attach" debug configuration. For attaching, "address" and "port" must be specified (please note that "address" must be set to "localhost" since remote debugging is not yet supported). Port should be the one that the debug startup process returned above.

Once your application is running on the port specified, you can change the debug target in the dropdown next to the play/run icon.