Write to spawned process stdin nodejs?

Question

I have a script that I want to run from another one. The problem is that the child script (process) needs an user input before it continues.

var child = spawn('script');
child.stdin.setEncoding('utf8');
child.stdout.on('data', function (data) {
    console.log(data.toString().trim()); // tells me to input my data
    child.stdin.write('my data\n');
});

After I input my data the child script should continue but instead it hang in there.

Solution

Actually the above code work for me. I'm using commander.js in the child script to prompt the user for action. Here is how I respond to a child's script prompt:

child.stdout.on('data', function (data) {
    switch (data.toString().trim()) {
        case 'Username:':
            child.stdin.write('user');
            break;
        case 'Password:':
            child.stdin.write('pass');
            break;
    }
});

Same thing work with suppose:

var suppose = require('suppose');

suppose('script')
    .on('Username: ').respond('user')
    .on('Password: ').respond('pass')
.error(function (err) {
    console.log(err.message);
})
.end(function (code) {
    console.log(code);
    done();
});

Answer 1

You could use the package suppose. It's like Unix Expect. Full disclosure, I'm the author.

From the example on the Github page, you can see an example of it scripting NPM: https://github.com/jprichardson/node-suppose

Example:

var suppose = require('suppose')
suppose('script')
.on(/\w*/).respond('my data\n')
.end(function(code){
  console.log('Done: ' + code); 
})