Binary search array - Node.js Algorithm

Node.js examples for Algorithm:Search

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Description

Binary search array

Demo Code

function BinarySearch(haystack, needle, comparator) {
  var low = 0, high = haystack.length - 1, comp = -1, mid = 0;

  if (typeof comparator != 'function') {
    comparator = function(needle, item, index) {
      if (needle < item) return -1;
      if (needle > item) return 1;
      else return 0;
    };/* w w w  .  j a  v a  2  s.com*/
  }
  
  while (low <= high) {
    var mid = Math.floor((low + high) / 2);
    var comp = comparator(needle, haystack[mid], mid);
    
    if (comp < 0) {
      high = mid - 1;
    }
    else if (comp > 0) {
      low = mid + 1;
    }
    else {
      return mid;
    }
  }

  if (comp < 0) return -1 - mid;
  if (comp > 0) return -2 - mid;
}

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