Problems with number inputs on discord.js

I am having issues with a timer command in discord.js. I'd like to check if the user inputted a valid time as an argument:

case 'timer':
  let time = args[1];
  if(!time) {
    return message.reply("<:what:784258557067526174> Please specify a time!");
  }
  message.reply(`Timer started for ${ms(ms(time))}`)

  setTimeout(function(){
    message.reply('your timer has ended')
  }, ms(time));
  break;

The way the code is supposed to work is seen in the first example in the image. If the user type the command with a valid time, the bot starts a timer and responds with "Timer started for %time%".

But I want it to respond with a certain message if an invalid input is entered, as seen in the second example in the image:

Read more here: https://stackoverflow.com/questions/65710548/problems-with-number-inputs-on-discord-js