imitation game - final exam - fundamentals

function imitationGame(input) {
  let textToDecode = input.shift();

  let actions = {
    'ChangeAll': changeall,
    'Move': move,
    'Insert': insertletter,
  };

  while (input[0] !== "Decode") {
    let line = input.shift();
    let [command, param1, param2] = line.split("|");
    let action = actions[command];
    action(param1, param2);

  }
  console.log(`The decrypted message is: ${textToDecode}`);

  function changeall(param1, param2) {
    while(textToDecode.includes(param1)){
    textToDecode = textToDecode.replace(param1, param2);
  }
}
  function move(n,param2){
    n = Number(n);
    let left= textToDecode.substring(0,n);
    let right = textToDecode.substring(n);
    textToDecode = right+ left;
  }
  function insertletter(param1,param2){
      param1 = Number(param1);

      let left = textToDecode.substring(0,param1);
      let right = textToDecode.substring(param1);
      textToDecode = left + param2 + right;

  }
}