Bump to v4.0.0.

join.js

@@ -0,0 +1,28 @@
+define([], function() {
+
+  /** Used for built-in method references. */
+  var arrayProto = 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) : '';
+  }
+
+  return join;
+});