Insertion sort javascript version

insertion-sort.js

function insertionSort(data)
{
  for(let i = 1; i < data.length; ++i) {
    let j = i
    while(j > 0 && data[j] < data[j - 1]) {
      let tmp = data[j]
      data[j] = data[j - 1]
      data[j - 1] = tmp
      j --
    }
  }
}

data = Array.from({length: 20}).map(() => Math.floor(Math.random() * 20))
console.log(data)
insertionSort(data)
console.log(data)

• Insertion sort. notice index out of range.
  a better insertion introduction with generator.