From 07d8b06d4162fa736247a3c150c00c2146372cab Mon Sep 17 00:00:00 2001
From: Valentin Shergin <shergin@fb.com>
Date: Mon, 15 Oct 2018 23:23:34 -0700
Subject: [PATCH] Fabric: TextAttributes::defaultTextAttributes()

Summary: An `AttributedString` object generated by a cross-platform layer of React Native must have already resolved text styles to make the actual resulting text identical across platforms. To do so we have to have a unified default.

Reviewed By: sahrens

Differential Revision: D10287725

fbshipit-source-id: e8c62b33496be34146182baccd0009d3624a7fe5
---
 .../fabric/attributedstring/TextAttributes.cpp       | 12 ++++++++++++
 ReactCommon/fabric/attributedstring/TextAttributes.h |  7 +++++++
 .../text/paragraph/ParagraphShadowNode.cpp           |  5 ++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/ReactCommon/fabric/attributedstring/TextAttributes.cpp b/ReactCommon/fabric/attributedstring/TextAttributes.cpp
index ee31969dd14..43f87235a09 100644
--- a/ReactCommon/fabric/attributedstring/TextAttributes.cpp
+++ b/ReactCommon/fabric/attributedstring/TextAttributes.cpp
@@ -149,6 +149,18 @@ bool TextAttributes::operator!=(const TextAttributes &rhs) const {
   return !(*this == rhs);
 }
 
+TextAttributes TextAttributes::defaultTextAttributes() {
+  static auto textAttributes = [] {
+    auto textAttributes = TextAttributes{};
+    // Non-obvious (can be different among platforms) default text attributes.
+    textAttributes.foregroundColor = blackColor();
+    textAttributes.backgroundColor = clearColor();
+    textAttributes.fontSize = 12.0;
+    return textAttributes;
+  }();
+  return textAttributes;
+}
+
 #pragma mark - DebugStringConvertible
 
 #if RN_DEBUG_STRING_CONVERTIBLE
diff --git a/ReactCommon/fabric/attributedstring/TextAttributes.h b/ReactCommon/fabric/attributedstring/TextAttributes.h
index cfd103a7893..e0acba57681 100644
--- a/ReactCommon/fabric/attributedstring/TextAttributes.h
+++ b/ReactCommon/fabric/attributedstring/TextAttributes.h
@@ -27,6 +27,13 @@ using SharedTextAttributes = std::shared_ptr<const TextAttributes>;
 
 class TextAttributes : public DebugStringConvertible {
  public:
+  /*
+   * Returns TextAttribute object which has actual default attribute values
+   * (e.g. `foregroundColor = black`), in oppose to TextAttribute's default
+   * constructor which creates an object with nulled attributes.
+   */
+  static TextAttributes defaultTextAttributes();
+
 #pragma mark - Fields
 
   // Color
diff --git a/ReactCommon/fabric/components/text/paragraph/ParagraphShadowNode.cpp b/ReactCommon/fabric/components/text/paragraph/ParagraphShadowNode.cpp
index 640a8cad40f..245dcee932f 100644
--- a/ReactCommon/fabric/components/text/paragraph/ParagraphShadowNode.cpp
+++ b/ReactCommon/fabric/components/text/paragraph/ParagraphShadowNode.cpp
@@ -16,8 +16,11 @@ const char ParagraphComponentName[] = "Paragraph";
 
 AttributedString ParagraphShadowNode::getAttributedString() const {
   if (!cachedAttributedString_.has_value()) {
+    auto textAttributes = TextAttributes::defaultTextAttributes();
+    textAttributes.apply(getProps()->textAttributes);
+
     cachedAttributedString_ = BaseTextShadowNode::getAttributedString(
-        getProps()->textAttributes, shared_from_this());
+        textAttributes, shared_from_this());
   }
 
   return cachedAttributedString_.value();