Bump to v4.0.0.

join.js

@@ -0,0 +1,25 @@
+/** Used for built-in method references. */
+var arrayProto = global.Array.prototype;
+
+/* Built-in method references for those with the same name as other `lodash` methods. */
+var nativeJoin = arrayProto.join;
+
+/**
+ * Converts all elements in `array` into a string separated by `separator`.
+ *
+ * @static
+ * @memberOf _
+ * @category Array
+ * @param {Array} array The array to convert.
+ * @param {string} [separator=','] The element separator.
+ * @returns {string} Returns the joined string.
+ * @example
+ *
+ * _.join(['a', 'b', 'c'], '~');
+ * // => 'a~b~c'
+ */
+function join(array, separator) {
+  return array ? nativeJoin.call(array, separator) : '';
+}
+
+module.exports = join;