Add RawValue support for arrays of arrays

Summary: Adds support for dynamic value that are `std::vector<std::vector<RawValue>>`

Reviewed By: shergin, mdvacca

Differential Revision: D16936932

fbshipit-source-id: fc8d087f9705af9da56ccc1bd9a0537b2bfeb50d

ReactCommon/fabric/core/primitives/RawValue.h

@@ -250,6 +250,19 @@ class RawValue {
     return result;
   }
 
+  template <typename T>
+  static std::vector<std::vector<T>> castValue(
+      const folly::dynamic &dynamic,
+      std::vector<std::vector<T>> *type) noexcept {
+    assert(dynamic.isArray());
+    auto result = std::vector<std::vector<T>>{};
+    result.reserve(dynamic.size());
+    for (const auto &item : dynamic) {
+      result.push_back(castValue(item, (std::vector<T> *)nullptr));
+    }
+    return result;
+  }
+
   template <typename T>
   static better::map<std::string, T> castValue(
       const folly::dynamic &dynamic,

ReactCommon/fabric/core/propsConversions.h

@@ -46,6 +46,31 @@ void fromRawValue(RawValue const &rawValue, std::vector<T> &result) {
   result.push_back(itemResult);
 }
 
+template <typename T>
+void fromRawValue(
+    RawValue const &rawValue,
+    std::vector<std::vector<T>> &result) {
+  if (rawValue.hasType<std::vector<std::vector<RawValue>>>()) {
+    auto items = (std::vector<std::vector<RawValue>>)rawValue;
+    auto length = items.size();
+    result.clear();
+    result.reserve(length);
+    for (int i = 0; i < length; i++) {
+      T itemResult;
+      fromRawValue(items.at(i), itemResult);
+      result.push_back(itemResult);
+    }
+    return;
+  }
+
+  // The case where `value` is not an array.
+  result.clear();
+  result.reserve(1);
+  T itemResult;
+  fromRawValue(rawValue, itemResult);
+  result.push_back(itemResult);
+}
+
 template <typename T, typename U = T>
 T convertRawProp(
     RawProps const &rawProps,