Node.js Readline and CLI keypress example

readline-test.js

var readline = require('readline'),
    _ = require('lodash'),
    charm = require('charm')(process.stdout),
    rl = readline.createInterface(process.stdin, process.stdout);

var selected = 0;
var choices = [
  "foo",
  "bar",
  "javascript",
  "bleurp"
];

function renderChoices() {
  choices.forEach(function( choice, i ) {
    charm.foreground("cyan");
    charm.write("[" + (i === selected ? "X" : " ") + "] ");
    (i !== selected) && charm.foreground("white");
    charm.write(choice + "\r\n");
    charm.foreground("white");
  });
}

process.stdin.on('keypress', function(s, key) {
  if( key.name === "up" && (selected - 1) >= 0 ) {
    selected--;
  } else if( key.name === "down" && (selected + 1) < choices.length ){
    selected++;
  } else {
    return; // don't render if nothing changed
  }
  charm.erase("line");
  choices.forEach(function() {
    charm.up(1);
    charm.erase("line");
  });
  renderChoices();
});

renderChoices();

rl.on('line', function(line) {
  charm.write("You choosed: " + choices[selected] + "\r\n");
  process.exit(0);
}).on('close', function() {
  console.log('Have a great day!');
  rl.close();
  process.exit(0);
});