Function createPredicateIndexFinder

underscore.js:1277–1287

(dir)

  // Internal function to generate `_.findIndex` and `_.findLastIndex`.
  function createPredicateIndexFinder(dir) {
    return function(array, predicate, context) {
      predicate = cb(predicate, context);
      var length = getLength(array);
      var index = dir > 0 ? 0 : length - 1;
      for (; index >= 0 && index < length; index += dir) {
        if (predicate(array[index], index, array)) return index;
      }
      return -1;
    };
  }

  // Returns the first index on an array-like that passes a truth test.
  var findIndex = createPredicateIndexFinder(1);