Small optimization to avoid serializing runtime source unnecessarily

For source that have source maps, the original source is retrieved using the source map. We only fall back to parsing the full source code is when there's no source map.

The source is (potentially) very large, so we can avoid the overhead of serializing it unnecessarily to share it with the worker in this case.

Author: Brian Vaughn

packages/react-devtools-extensions/src/parseHookNames/loadSourceAndMetadata.js

@@ -200,6 +200,13 @@ function extractAndLoadSourceMapJSON(
           if (sourceMapIncludesSource(sourceMapJSON, runtimeSourceURL)) {
             hookSourceAndMetadata.sourceMapJSON = sourceMapJSON;
 
+            // OPTIMIZATION If we've located a source map for this source,
+            // we'll use it to retrieve the original source (to extract hook names).
+            // We only fall back to parsing the full source code is when there's no source map.
+            // The source is (potentially) very large,
+            // So we can avoid the overhead of serializing it unnecessarily.
+            hookSourceAndMetadata.runtimeSourceCode = null;
+
             break;
           }
         } else {
@@ -272,7 +279,16 @@ function extractAndLoadSourceMapJSON(
 
           setterPromises.push(
             fetchPromise.then(sourceMapJSON => {
-              hookSourceAndMetadata.sourceMapJSON = sourceMapJSON;
+              if (sourceMapJSON !== null) {
+                hookSourceAndMetadata.sourceMapJSON = sourceMapJSON;
+
+                // OPTIMIZATION If we've located a source map for this source,
+                // we'll use it to retrieve the original source (to extract hook names).
+                // We only fall back to parsing the full source code is when there's no source map.
+                // The source is (potentially) very large,
+                // So we can avoid the overhead of serializing it unnecessarily.
+                hookSourceAndMetadata.runtimeSourceCode = null;
+              }
             }),
           );
         });