[ReactNative] Make JS stack traces in Xcode prettier

Libraries/JavaScriptAppEngine/Initialization/parseErrorStack.js

@@ -0,0 +1,40 @@
+/**
+ * Copyright 2004-present Facebook. All Rights Reserved.
+ *
+ * @providesModule parseErrorStack
+ */
+'use strict';
+
+var stacktraceParser = require('stacktrace-parser');
+
+function resolveSourceMaps(sourceMapInstance, stackFrame) {
+  try {
+    var orig = sourceMapInstance.originalPositionFor({
+      line: stackFrame.lineNumber,
+      column: stackFrame.column,
+    });
+    if (orig) {
+      stackFrame.file = orig.source;
+      stackFrame.lineNumber = orig.line;
+      stackFrame.column = orig.column;
+    }
+  } catch (innerEx) {
+  }
+}
+
+function parseErrorStack(e, sourceMapInstance) {
+  var stack = stacktraceParser.parse(e.stack);
+
+  var framesToPop = e.framesToPop || 0;
+  while (framesToPop--) {
+    stack.shift();
+  }
+
+  if (sourceMapInstance) {
+    stack.forEach(resolveSourceMaps.bind(null, sourceMapInstance));
+  }
+
+  return stack;
+}
+
+module.exports = parseErrorStack;