How to hide password in the nodejs console

Question

I want to hide password input. I see many answers in stackoverflow but I can't verify value if I press backspace. The condition return false.

I tried several solution to overwrite the function but I got an issue with buffer if I press backspace, I got invisible character \b.

I press : "A", backspace, "B", I have in my buffer this : "\u0041\u0008\u0042" (toString() = 'A\bB') and not "B".

I have :

var readline = require('readline');

var rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

rl.question("password : ", function(password) {
    console.log("Your password : " + password);
});

Answer 1

Hello @kartik,

To hide your password input, you can use :

password : [-=]
password : [=-]

The code :

var readline = require('readline');

var rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

rl.stdoutMuted = true;

rl.query = "Password : ";
rl.question(rl.query, function(password) {
  console.log('\nPassword is ' + password);
  rl.close();
});

rl._writeToOutput = function _writeToOutput(stringToWrite) {
  if (rl.stdoutMuted)
    rl.output.write("\x1B[2K\x1B[200D"+rl.query+"["+((rl.line.length%2==1)?"=-":"-=")+"]");
  else
    rl.output.write(stringToWrite);
};

This sequence "\x1B[2K\x1BD" uses two escapes sequences :

• Esc [2K : clear entire line.
• Esc D : move/scroll window up one line.

Hope it helps!!

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Thank You!!