Add support for JSResource in Metro

Reviewed By: cpojer Differential Revision: D17527390 fbshipit-source-id: 6bf971038ab23d1c56401099bdf6c72fbde5aa73
facebook · Sep 30, 2019 · 662b416 · 662b416
1 parent a1caae7
commit 662b416
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Showing 2 changed files with 44 additions and 3 deletions.
diff --git a/packages/metro/src/ModuleGraph/worker/__tests__/collectDependencies-test.js b/packages/metro/src/ModuleGraph/worker/__tests__/collectDependencies-test.js
@@ -105,6 +105,22 @@ it('collects mixed dependencies as being sync; reverse order', () => {
   );
 });
 
+it('collects __jsResource calls', () => {
+  const ast = astFromCode(`
+    __jsResource("some/async/module");
+  `);
+  const {dependencies, dependencyMapName} = collectDependencies(ast, opts);
+  expect(dependencies).toEqual([
+    {name: 'some/async/module', data: {isAsync: true}},
+    {name: 'asyncRequire', data: {isAsync: false}},
+  ]);
+  expect(codeFromAst(ast)).toEqual(
+    comparableCode(`
+      require(${dependencyMapName}[1], "asyncRequire").resource(${dependencyMapName}[0], "some/async/module");
+    `),
+  );
+});
+
 describe('import() prefetching', () => {
   it('collects prefetch calls', () => {
     const ast = astFromCode(`

diff --git a/packages/metro/src/ModuleGraph/worker/collectDependencies.js b/packages/metro/src/ModuleGraph/worker/collectDependencies.js
@@ -30,6 +30,7 @@ opaque type Path = any;
 
 type DepOptions = {|
   +prefetchOnly: boolean,
+  +jsResource?: boolean,
 |};
 
 type InternalDependency<D> = {|
@@ -104,6 +105,10 @@ const makeAsyncPrefetchTemplate = template(`
   require(ASYNC_REQUIRE_MODULE_PATH).prefetch(MODULE_ID, MODULE_NAME)
 `);
 
+const makeJSResourceTemplate = template(`
+  require(ASYNC_REQUIRE_MODULE_PATH).resource(MODULE_ID, MODULE_NAME)
+`);
+
 /**
  * Transform all the calls to `require()` and `import()` in a file into ID-
  * independent code, and return the list of dependencies. For example, a call
@@ -141,12 +146,24 @@ function collectDependencies(
       const name = callee.node.name;
 
       if (callee.isImport()) {
-        processImportCall(path, state, {prefetchOnly: false});
+        processImportCall(path, state, {
+          prefetchOnly: false,
+        });
         return;
       }
 
       if (name === '__prefetchImport' && !path.scope.getBinding(name)) {
-        processImportCall(path, state, {prefetchOnly: true});
+        processImportCall(path, state, {
+          prefetchOnly: true,
+        });
+        return;
+      }
+
+      if (name === '__jsResource' && !path.scope.getBinding(name)) {
+        processImportCall(path, state, {
+          prefetchOnly: false,
+          jsResource: true,
+        });
         return;
       }
 
@@ -219,7 +236,15 @@ function processImportCall(
   );
   const MODULE_NAME = types.stringLiteral(name);
 
-  if (!options.prefetchOnly) {
+  if (options.jsResource) {
+    path.replaceWith(
+      makeJSResourceTemplate({
+        ASYNC_REQUIRE_MODULE_PATH,
+        MODULE_ID,
+        MODULE_NAME,
+      }),
+    );
+  } else if (!options.prefetchOnly) {
     path.replaceWith(
       makeAsyncRequireTemplate({
         ASYNC_REQUIRE_MODULE_PATH,