Function sortedIndex

underscore.js:1297–1306

(array, obj, iteratee, context)

  // Use a comparator function to figure out the smallest index at which
  // an object should be inserted so as to maintain order. Uses binary search.
  function sortedIndex(array, obj, iteratee, context) {
    iteratee = cb(iteratee, context, 1);
    var value = iteratee(obj);
    var low = 0, high = getLength(array);
    while (low < high) {
      var mid = Math.floor((low + high) / 2);
      if (iteratee(array[mid]) < value) low = mid + 1; else high = mid;
    }
    return low;
  }

  // Internal function to generate the `_.indexOf` and `_.lastIndexOf` functions.
  function createIndexFinder(dir, predicateFind, sortedIndex) {