Bump to v4.0.0.

tap.js

@@ -0,0 +1,28 @@
+/**
+ * This method invokes `interceptor` and returns `value`. The interceptor is
+ * invoked with one argument; (value). The purpose of this method is to "tap into"
+ * a method chain in order to perform operations on intermediate results within
+ * the chain.
+ *
+ * @static
+ * @memberOf _
+ * @category Seq
+ * @param {*} value The value to provide to `interceptor`.
+ * @param {Function} interceptor The function to invoke.
+ * @returns {*} Returns `value`.
+ * @example
+ *
+ * _([1, 2, 3])
+ *  .tap(function(array) {
+ *    array.pop();
+ *  })
+ *  .reverse()
+ *  .value();
+ * // => [2, 1]
+ */
+function tap(value, interceptor) {
+  interceptor(value);
+  return value;
+}
+
+export default tap;