Binary Search

search.js

function search(key, data) {
  var min = 0;
  var max = data.length - 1;
  var half;

  while (max >= min) {
    half = Math.floor((max + min)/2);

    if (data[half] === key) {
      return half;
    } else if (data[half] < key) {
      min = half + 1;
    } else if (data[half] > key) {
      max = half - 1;
    }
  }
  return -1;
}