Add edgeSortedIndex.

lodash.js

@@ -1014,7 +1014,7 @@
      * Creates a `lodash` object which wraps `value` to enable intuitive chaining.
      * Methods that operate on and return arrays, collections, and functions can
      * be chained together. Methods that return a boolean or single value will
-     * automatically end the chain returning the unwrapped result. Explicit chaining
+     * automatically end the chain returning the unwrapped value. Explicit chaining
      * may be enabled by using `_.chain`. The execution of chained methods is lazy,
      * that is, execution is deferred until `_#value` is implicitly or explicitly
      * called.
@@ -2604,29 +2604,20 @@
           high = array ? array.length : low;
 
       value = iteratee(value);
-
+      if (value !== value || typeof value == 'undefined' || high > (MAX_ARRAY_LENGTH / 2)) {
-      var valIsNaN = value !== value,
+        return edgeSortedIndex(array, value, iteratee, retHighest);
-          valIsUndef = typeof value == 'undefined';
+      }
-
       while (low < high) {
-        var mid = floor((low + high) / 2),
+        var mid = (low + high) >>> 1,
-            computed = iteratee(array[mid]),
+            computed = iteratee(array[mid]);
-            isReflexive = computed === computed;
 
-        if (valIsNaN) {
+        if (retHighest ? (computed <= value) : (computed < value)) {
-          var setLow = isReflexive || retHighest;
-        } else if (valIsUndef) {
-          setLow = isReflexive && (retHighest || typeof computed != 'undefined');
-        } else {
-          setLow = retHighest ? (computed <= value) : (computed < value);
-        }
-        if (setLow) {
           low = mid + 1;
         } else {
           high = mid;
         }
       }
-      return nativeMin(high, MAX_ARRAY_INDEX);
+      return high;
     }
 
     /**
@@ -3181,6 +3172,46 @@
       return setter(result, newData);
     }
 
+    /**
+     * The base implementation of `_.sortedIndex` and `_.sortedLastIndex` without
+     * support for callback shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {boolean} [retHighest=false] Specify returning the highest, instead
+     *  of the lowest, index at which a value should be inserted into `array`.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     */
+    function edgeSortedIndex(array, value, iteratee, retHighest) {
+      var low = 0,
+          high = array ? array.length : low,
+          valIsNaN = value !== value,
+          valIsUndef = typeof value == 'undefined';
+
+      while (low < high) {
+        var mid = floor((low + high) / 2),
+            computed = iteratee(array[mid]),
+            isReflexive = computed === computed;
+
+        if (valIsNaN) {
+          var setLow = isReflexive || retHighest;
+        } else if (valIsUndef) {
+          setLow = isReflexive && (retHighest || typeof computed != 'undefined');
+        } else {
+          setLow = retHighest ? (computed <= value) : (computed < value);
+        }
+        if (setLow) {
+          low = mid + 1;
+        } else {
+          high = mid;
+        }
+      }
+      return nativeMin(high, MAX_ARRAY_INDEX);
+    }
+
     /**
      * Gets the appropriate "callback" function. If the `_.callback` method is
      * customized this function returns the custom method, otherwise it returns