binary-search.ts

// O(logn)
const binarySearch = (list: number[], item) => {
  let [from, to] = [0, list.length - 1];
  
  if (!item) return
  
  while (from <= to) {
    const index = Math.ceil((from + to) / 2);
    const guess = list[index];
    
    if (guess === item) return index;
    if (guess > item) to = index - 1;
    else from = index + 2;
  }
  
  return null;
}

const seed = Array(10).fill().map((item, index) => index + 1)

binarySearch(seed, 2)