我如何在javascript中实现这个功能

Question

i am in a bootcamp and i got stuck here, i tried to do it by myself and it didn't worked, then i copy and paste the code that the mentor wrote, and is not working also for some reason, i should get a random color into the gamePattern variable.. any ideas ? Thank you.

var buttonColours = ["red", "blue", "green", "yellow"];

var gamePattern = [];

function nextSequence() {

  var randomNumber = Math.floor(Math.random() * 4);
  var randomChosenColour = buttonColours[randomNumber];
  gamePattern.push(randomChosenColour);

Answer 1

First of all, in your code nextSequence is missing a closing bracket } and you would need call the function nextSequence() at the end to actually execute your logic.

However, I'd recommend to avoid functions that change values of the global scope because this easily becomes a pitfall for untraceable errors and application behavior. Therefore, I'd recommend to have this helper function randomChoiceFromList that gives you a random item from a list. Furthermore, as it is more abstract it is potentially reusable.

 var buttonColours = ["red", "blue", "green", "yellow"]; var gamePattern = []; function randomChoiceFromList(list) { const randomNumber = Math.floor(Math.random() * (list.length)); return list[randomNumber]; }; gamePattern.push(randomChoiceFromList(buttonColours)); console.log(gamePattern);