01. World Tour js exam

function solve(arg) {
  let dest = arg.shift();
  let commandLine = arg.shift();

  function insert(str, index, value) {
    return str.substr(0, index) + value + str.substr(index);
  }


  while (commandLine !== 'Travel') {
    const [command, firstArument, secondArgument] = commandLine.split(':');

    switch (command) {
      case 'Add Stop': {
        const indexStr = Number(firstArument);
        const takeChar = dest[indexStr];
        if (dest.indexOf(takeChar) !== -1) {
          dest = insert(dest, indexStr, secondArgument);

        }else{

          console.log(`${dest}`);
        }

      }
      case 'Remove Stop': {
        const startIndex = Number(firstArument);
        const endIndex = Number(secondArgument);

        if (dest.indexOf(dest[startIndex]) !== -1 && dest.indexOf(dest[endIndex]) !== -1) {
          dest = dest.slice(0, startIndex) + dest.slice(endIndex + 1);

        }
        console.log(`${dest}`);

        break;
      }
      case 'Switch': {
        if (dest.includes(firstArument)) {
          dest = dest.replace(firstArument, secondArgument);

        }
        console.log(`${dest}`);
        break;
      }

    }

    commandLine = arg.shift();
  }

  console.log(`Ready for world tour! Planned stops: ${dest}`);
}