Izmjenjena struktura, dodan backand

web/node_modules/react-dom/lib/shouldUpdateReactComponent.js

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+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+
+'use strict';
+
+/**
+ * Given a `prevElement` and `nextElement`, determines if the existing
+ * instance should be updated as opposed to being destroyed or replaced by a new
+ * instance. Both arguments are elements. This ensures that this logic can
+ * operate on stateless trees without any backing instance.
+ *
+ * @param {?object} prevElement
+ * @param {?object} nextElement
+ * @return {boolean} True if the existing instance should be updated.
+ * @protected
+ */
+
+function shouldUpdateReactComponent(prevElement, nextElement) {
+  var prevEmpty = prevElement === null || prevElement === false;
+  var nextEmpty = nextElement === null || nextElement === false;
+  if (prevEmpty || nextEmpty) {
+    return prevEmpty === nextEmpty;
+  }
+
+  var prevType = typeof prevElement;
+  var nextType = typeof nextElement;
+  if (prevType === 'string' || prevType === 'number') {
+    return nextType === 'string' || nextType === 'number';
+  } else {
+    return nextType === 'object' && prevElement.type === nextElement.type && prevElement.key === nextElement.key;
+  }
+}
+
+module.exports = shouldUpdateReactComponent;