1  var isSymbol = require('./isSymbol');
 2  
 3  /** Used as references for the maximum length and index of an array. */
 4  var MAX_ARRAY_LENGTH = 4294967295,
 5      MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1;
 6  
 7  /* Built-in method references for those with the same name as other `lodash` methods. */
 8  var nativeFloor = Math.floor,
 9      nativeMin = Math.min;
10  
11  /**
12   * The base implementation of `_.sortedIndexBy` and `_.sortedLastIndexBy`
13   * which invokes `iteratee` for `value` and each element of `array` to compute
14   * their sort ranking. The iteratee is invoked with one argument; (value).
15   *
16   * @private
17   * @param {Array} array The sorted array to inspect.
18   * @param {*} value The value to evaluate.
19   * @param {Function} iteratee The iteratee invoked per element.
20   * @param {boolean} [retHighest] Specify returning the highest qualified index.
21   * @returns {number} Returns the index at which `value` should be inserted
22   *  into `array`.
23   */
24  function baseSortedIndexBy(array, value, iteratee, retHighest) {
25    var low = 0,
26        high = array == null ? 0 : array.length;
27    if (high === 0) {
28      return 0;
29    }
30  
31    value = iteratee(value);
32    var valIsNaN = value !== value,
33        valIsNull = value === null,
34        valIsSymbol = isSymbol(value),
35        valIsUndefined = value === undefined;
36  
37    while (low < high) {
38      var mid = nativeFloor((low + high) / 2),
39          computed = iteratee(array[mid]),
40          othIsDefined = computed !== undefined,
41          othIsNull = computed === null,
42          othIsReflexive = computed === computed,
43          othIsSymbol = isSymbol(computed);
44  
45      if (valIsNaN) {
46        var setLow = retHighest || othIsReflexive;
47      } else if (valIsUndefined) {
48        setLow = othIsReflexive && (retHighest || othIsDefined);
49      } else if (valIsNull) {
50        setLow = othIsReflexive && othIsDefined && (retHighest || !othIsNull);
51      } else if (valIsSymbol) {
52        setLow = othIsReflexive && othIsDefined && !othIsNull && (retHighest || !othIsSymbol);
53      } else if (othIsNull || othIsSymbol) {
54        setLow = false;
55      } else {
56        setLow = retHighest ? (computed <= value) : (computed < value);
57      }
58      if (setLow) {
59        low = mid + 1;
60      } else {
61        high = mid;
62      }
63    }
64    return nativeMin(high, MAX_ARRAY_INDEX);
65  }
66  
67  module.exports = baseSortedIndexBy;