即使在页面重新加载后，如何随机生成不重复的数字？

Question

Question: How do I generate non-repeating numbers even after page reload? (Example: 0 -> 100, I would get 10 once, and never again until seeing every other number.)

Preferred Answer: Code block or explanation showing how to generate non-repeating numbers that won't repeat after reloading the page.

Answer 1

The easiest way is to save the 'seen' numbers in a form of an object in a cookie or localStorage, for example like that:

const seenNumbers = {
  51: true,
  64: true
} 

Then every time you load the page, you load this array and try to generate a new number. Before using it, you check whether it is in seenNumbers and if it is, you try to generate a new one until you get a new number that was not used before. After that, you add it to the seenNumbers and save the cookie.

Don't forget to have the logic in case of seenNumbers have all the numbers, then your code will try to generate new items forever. To avoid that, first check the number of items in seenNumbers , and if it equals the number of possible numbers, you do not generate any numbers.