Unify worker module map transmission w/ small perf benefit.

packages/jest-runner/src/index.ts

@@ -103,16 +103,13 @@ class TestRunner {
     onResult: OnTestSuccess,
     onFailure: OnTestFailure,
   ) {
-    let resolvers: Map<string, SerializableResolver> | undefined = undefined;
-    if (watcher.isWatchMode()) {
-      resolvers = new Map();
-      for (const test of tests) {
-        if (!resolvers.has(test.context.config.name)) {
-          resolvers.set(test.context.config.name, {
-            config: test.context.config,
-            serializableModuleMap: test.context.moduleMap.toJSON(),
-          });
-        }
+    const resolvers: Map<string, SerializableResolver> = new Map();
+    for (const test of tests) {
+      if (!resolvers.has(test.context.config.name)) {
+        resolvers.set(test.context.config.name, {
+          config: test.context.config,
+          serializableModuleMap: test.context.moduleMap.toJSON(),
+        });
       }
     }
 
@@ -121,13 +118,11 @@ class TestRunner {
       forkOptions: {stdio: 'pipe'},
       maxRetries: 3,
       numWorkers: this._globalConfig.maxWorkers,
-      setupArgs: resolvers
-        ? [
-            {
-              serializableResolvers: Array.from(resolvers.values()),
-            },
-          ]
-        : undefined,
+      setupArgs: [
+        {
+          serializableResolvers: Array.from(resolvers.values()),
+        },
+      ],
     }) as WorkerInterface;
 
     if (worker.getStdout()) worker.getStdout().pipe(process.stdout);

packages/jest-runner/src/testWorker.ts

@@ -53,34 +53,25 @@ const formatError = (error: string | ErrorWithCode): SerializableError => {
 };
 
 const resolvers = new Map<string, Resolver>();
-const getResolver = (config: Config.ProjectConfig, moduleMap?: ModuleMap) => {
-  const name = config.name;
-  if (moduleMap || !resolvers.has(name)) {
-    resolvers.set(
-      name,
-      Runtime.createResolver(
-        config,
-        moduleMap || Runtime.createHasteMap(config).readModuleMap(),
-      ),
-    );
+const getResolver = (config: Config.ProjectConfig) => {
+  const resolver = resolvers.get(config.name);
+  if (!resolver) {
+    throw new Error('Cannot find resolver for: ' + config.name);
   }
-  return resolvers.get(name)!;
+  return resolver;
 };
 
-export function setup(setupData?: {
+export function setup(setupData: {
   serializableResolvers: Array<SerializableResolver>;
 }) {
-  // Setup data is only used in watch mode to pass the latest version of all
-  // module maps that will be used during the test runs. Otherwise, module maps
-  // are loaded from disk as needed.
-  if (setupData) {
-    for (const {
-      config,
-      serializableModuleMap,
-    } of setupData.serializableResolvers) {
-      const moduleMap = HasteMap.ModuleMap.fromJSON(serializableModuleMap);
-      getResolver(config, moduleMap);
-    }
+  // Setup data is used in watch mode to pass all module maps that will be used
+  // during the test runs.
+  for (const {
+    config,
+    serializableModuleMap,
+  } of setupData.serializableResolvers) {
+    const moduleMap = HasteMap.ModuleMap.fromJSON(serializableModuleMap);
+    resolvers.set(config.name, Runtime.createResolver(config, moduleMap));
   }
 }