I need a function to create an array using 2 values such that:

• length: used to determine the new array length
• maxIndexValue: used to determine the max value at a given array index before starting back at 0.

example:

// length and maxIndexValue are integer values.
function buildArray(length, maxIndexValue){
  // TODO: Implementation
  return array;
}

let newArray = buildArray(16, 3)

// newArray should be [0,1,2,3,0,1,2,3,0,1,2,3,0,1,2,3]
console.log(newArray);

CodePudding user response：

You can easily achieve the result using % operator as

Array(length)
    .fill(0)
    .map((_, i) => i % (maxIndexValue   1));

or

new Array(length).fill(0).map((_, i) => i % (maxIndexValue   1));

function buildArray(length, maxIndexValue) {
  return Array(length)
    .fill(0)
    .map((_, i) => i % (maxIndexValue   1));
}

const length = 16,
  maxIndexValue = 3;
let newArray = buildArray(length, maxIndexValue);

console.log(newArray);

CodePudding user response：

This can be achieved using mod % operator.

function buildArray(length, maxIndexValue) {

  const arr = new Array(length);

  for (let a = 0; a < length; a  ) {
    // Using the mod % operator
    // 0 % 4 = 0
    // 1 % 4 = 1
    // 2 % 4 = 2
    // 3 % 4 = 4
    // 4 % 4 = 0
    // 5 % 4 = 1
    // .. so on
    arr[a] = a % (maxIndexValue   1);
  }

  return arr;
}

let newArray = buildArray(16, 3);
console.log(newArray);