Bump to v4.0.0.

internal/copyArray.js

@@ -0,0 +1,23 @@
+define([], function() {
+
+  /**
+   * Copies the values of `source` to `array`.
+   *
+   * @private
+   * @param {Array} source The array to copy values from.
+   * @param {Array} [array=[]] The array to copy values to.
+   * @returns {Array} Returns `array`.
+   */
+  function copyArray(source, array) {
+    var index = -1,
+        length = source.length;
+
+    array || (array = Array(length));
+    while (++index < length) {
+      array[index] = source[index];
+    }
+    return array;
+  }
+
+  return copyArray;
+});