javascript - Array with random unique integer numbers (0 to array.length - 1)

Question

This question is how to generate an array of all unique fixed integer numbers that the highest is equal to the length - 1 of the array.

An example of a result array: [3, 6, 4, 2, 1, 5, 0]

• All unique
• Random
• Highest number is in the highest number of the index (6)

This one is not: [3, 16, 4, 22, 19039, 555, 0]

Answer 1

First populate a sequential array, then sort by returning a random result in the compareFunction.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort

let arrLen?= 7, resArr = []
for(let i=0; i < arrLen; i++){
  resArr.push(i)
}

resArr.sort((a,b) => {
  let ranBool = Math.floor(Math.random() * 2)
  //returns 0 or -1, which either leaves the integers in place or sorts the second one before the first 
  return ranBool - 1
})

console.log(resArr)