Bump to v4.0.0.

internal/baseFill.js

@@ -1,3 +1,6 @@
+import toInteger from '../toInteger';
+import toLength from '../toLength';
+
 /**
  * The base implementation of `_.fill` without an iteratee call guard.
  *
@@ -11,18 +14,16 @@
 function baseFill(array, value, start, end) {
   var length = array.length;
 
-  start = start == null ? 0 : (+start || 0);
+  start = toInteger(start);
   if (start < 0) {
     start = -start > length ? 0 : (length + start);
   }
-  end = (end === undefined || end > length) ? length : (+end || 0);
+  end = (end === undefined || end > length) ? length : toInteger(end);
   if (end < 0) {
     end += length;
   }
-  length = start > end ? 0 : (end >>> 0);
-  start >>>= 0;
-
-  while (start < length) {
+  end = start > end ? 0 : toLength(end);
+  while (start < end) {
     array[start++] = value;
   }
   return array;