Bump to v4.0.0.

indexOf.js

@@ -0,0 +1,42 @@
+import baseIndexOf from './internal/baseIndexOf';
+import toInteger from './toInteger';
+
+/* Built-in method references for those with the same name as other `lodash` methods. */
+var nativeMax = Math.max;
+
+/**
+ * Gets the index at which the first occurrence of `value` is found in `array`
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons. If `fromIndex` is negative, it's used as the offset
+ * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
+ * performs a faster binary search.
+ *
+ * @static
+ * @memberOf _
+ * @category Array
+ * @param {Array} array The array to search.
+ * @param {*} value The value to search for.
+ * @param {number} [fromIndex=0] The index to search from.
+ * @returns {number} Returns the index of the matched value, else `-1`.
+ * @example
+ *
+ * _.indexOf([1, 2, 1, 2], 2);
+ * // => 1
+ *
+ * // using `fromIndex`
+ * _.indexOf([1, 2, 1, 2], 2, 2);
+ * // => 3
+ */
+function indexOf(array, value, fromIndex) {
+  var length = array ? array.length : 0;
+  if (!length) {
+    return -1;
+  }
+  fromIndex = toInteger(fromIndex);
+  if (fromIndex < 0) {
+    fromIndex = nativeMax(length + fromIndex, 0);
+  }
+  return baseIndexOf(array, value, fromIndex);
+}
+
+export default indexOf;