Adding color to repl prompt (node)

Question

I find that adding color to the prompt in repl really helps to separate the outputs. I achieved this by using NPM's chalk, but this adds a bunch of space between the prompt and the cursor.

var term = repl.start({
    prompt: chalk.blue('goose> '),
    eval: function(cmd, context, filename, cb){
        ...
    }
});

The prompt comes out like this ('|' is the cursor):

goose>              |

Any ideas on how to fix?

Answer 1

It turns out to be very simple:

var prompt = 'My fancy prompt >>> ';
rl.setPrompt(chalk.blue(prompt), prompt.length);

You need to specify the count of characters because readline doesn't understand that escape sequences are really displayed as zero width.

(This is based on Felix's answer.)