cursor-position-example.js

/**
 * Example on how to get cursor position programatically with JS 
 */

var stdin = process.stdin;

var firstAttempt = true;

function callback() {
  var buf = stdin.read();
  
  if(buf === null){
    if(firstAttempt){
      firstAttempt = false;
      console.log('1st call is always null, so we subscribe again');
      stdin.once('readable', callback);
      return;
    }
    //stdin.pause();
    stdin.setRawMode( false );
    return;
  }

  // detect cursor position: ESC[n;mR
  if (buf[0] === 27 && 
      buf[1] === '['.charCodeAt(0) && 
      buf[buf.length - 1] === 'R'.charCodeAt(0)) {
    var pos = buf.toString().slice(2, -1).split(';').map(Number);
    stdin.setRawMode( false );
    stdin.pause();
    console.log(' ---> position:', pos);
    return;
  }
  
  // Detect Ctrl + c, just in case...
  if(buf.length === 1 && buf[0] === 3){
    process.exist();
  };
  
  console.log('  --> oops: ' + buf);
  //process.stdout.write(buf);
}

// So we don't wait for enter'
stdin.setRawMode( true );

stdin.once('readable', callback);

process.stdout.write("some text to move the cursor");
process.stdout.write("\x1b[6n");

//stdin.resume();

cursor-position.js

/**
 * Attempt to create a module to read and return cursor position. So far not that great...
 */

var stdin = process.stdin;
var maxAttempts = 1;
var previousRawValue = stdin.isRaw;
stdin.setMaxListeners(50);

module.exports.getCursorPosition = function getCursorPosition(cb){
  cb = cb || function(){};

  var attempts = 0;
  
  // without this, we would only get streams once enter is pressed
  stdin.setRawMode( true );
  
  function callback() {
    var buf = stdin.read();
    
    if(buf === null){
      attempts++;
      if(attempts >= maxAttempts){
        //stdin.pause();
        stdin.setRawMode( previousRawValue );
        return cb();
      }
      // 1st call is always null, so we subscribe again
      stdin.once('readable', callback);
      return;
    }

    if (buf[0] === 27 && 
        buf[1] === '['.charCodeAt(0) && 
        buf[buf.length - 1] === 'R'.charCodeAt(0)) {
      var pos = buf.toString().slice(2, -1).split(';').map(Number);
      //stdin.pause();
      stdin.setRawMode( previousRawValue );
      console.log(' ---> success! ', pos);
      return cb(pos[0], pos[1]);
    }
    
    console.log('  --> oops:', buf);
    //process.stdout.write(buf);
  }
  
  stdin.once('readable', callback);
  process.stdout.write("\x1b[6n");
  //stdin.resume();
};

cursor-position2.js

/**
 * Attempt to create a module to read and return cursor position. Still no luck
 */


var stdin = process.stdin;
var previousRawValue = stdin.isRaw;
stdin.setMaxListeners(50);

module.exports.getCursorPosition = function getCursorPosition(cb){
  cb = cb || function(){};

 
  function callback(buf) {

    if (buf[0] === 27 && 
        buf[1] === '['.charCodeAt(0) && 
        buf[buf.length - 1] === 'R'.charCodeAt(0)) {
      var pos = buf.toString().slice(2, -1).split(';').map(Number);
      stdin.setRawMode( previousRawValue );
      stdin.removeListener('data', callback);
      stdin.pause();
//      console.log(' ---> success! ', pos);
      return cb(pos[0], pos[pos.length-1]);
    }
    
    console.log('  --> oops:', buf);
    process.stdout.write(buf);
  }
  
  // without this, we would only get streams once enter is pressed
  stdin.setRawMode( true );
  
  // resume stdin in the parent process (node app won't quit all by itself
  // unless an error or process.exit() happens)
  stdin.resume();
  
  stdin.on('data', callback);
  
  process.stdout.write("\x1b[6n");
  //stdin.resume();
};