feat: Move commonjs exports down for worklet files (#6316)

## Summary

Since Reanimated Babel Plugin breaks hoisting and [newer Typescript
hoists CommonJS exports by
default](microsoft/TypeScript#57669) we
sometimes need to dehoist those exports.

## Test plan

- [x] Add unit test suite.
- [x] Runtime tests pass.

packages/react-native-reanimated/__tests__/__snapshots__/plugin.test.ts.snap

@@ -990,6 +990,93 @@ exports[`babel plugin for file workletization doesn't workletize function outsid
 }"
 `;
 
+exports[`babel plugin for file workletization moves CommonJS export to the bottom of the file 1`] = `
+"var _worklet_15780239751281_init_data = {
+  code: "function foo_null1(){}",
+  location: "/dev/null",
+  sourceMap: "\\"mock source map\\"",
+  version: "x.y.z"
+};
+var foo = function () {
+  var _e = [new global.Error(), 1, -27];
+  var foo_null1 = function foo_null1() {};
+  foo_null1.__closure = {};
+  foo_null1.__workletHash = 15780239751281;
+  foo_null1.__initData = _worklet_15780239751281_init_data;
+  foo_null1.__stackDetails = _e;
+  return foo_null1;
+}();
+var bar = 1;
+exports.foo = foo;"
+`;
+
+exports[`babel plugin for file workletization moves multiple CommonJS exports to the bottom of the file 1`] = `
+"var _worklet_15780239751281_init_data = {
+  code: "function foo_null1(){}",
+  location: "/dev/null",
+  sourceMap: "\\"mock source map\\"",
+  version: "x.y.z"
+};
+var foo = function () {
+  var _e = [new global.Error(), 1, -27];
+  var foo_null1 = function foo_null1() {};
+  foo_null1.__closure = {};
+  foo_null1.__workletHash = 15780239751281;
+  foo_null1.__initData = _worklet_15780239751281_init_data;
+  foo_null1.__stackDetails = _e;
+  return foo_null1;
+}();
+var _worklet_552304524261_init_data = {
+  code: "function bar_null2(){}",
+  location: "/dev/null",
+  sourceMap: "\\"mock source map\\"",
+  version: "x.y.z"
+};
+var bar = function () {
+  var _e = [new global.Error(), 1, -27];
+  var bar_null2 = function bar_null2() {};
+  bar_null2.__closure = {};
+  bar_null2.__workletHash = 552304524261;
+  bar_null2.__initData = _worklet_552304524261_init_data;
+  bar_null2.__stackDetails = _e;
+  return bar_null2;
+}();
+var _worklet_9955902016844_init_data = {
+  code: "function baz_null3(){}",
+  location: "/dev/null",
+  sourceMap: "\\"mock source map\\"",
+  version: "x.y.z"
+};
+var baz = function () {
+  var _e = [new global.Error(), 1, -27];
+  var baz_null3 = function baz_null3() {};
+  baz_null3.__closure = {};
+  baz_null3.__workletHash = 9955902016844;
+  baz_null3.__initData = _worklet_9955902016844_init_data;
+  baz_null3.__stackDetails = _e;
+  return baz_null3;
+}();
+var _worklet_3271684035845_init_data = {
+  code: "function foobar_null4(){}",
+  location: "/dev/null",
+  sourceMap: "\\"mock source map\\"",
+  version: "x.y.z"
+};
+var foobar = function () {
+  var _e = [new global.Error(), 1, -27];
+  var foobar_null4 = function foobar_null4() {};
+  foobar_null4.__closure = {};
+  foobar_null4.__workletHash = 3271684035845;
+  foobar_null4.__initData = _worklet_3271684035845_init_data;
+  foobar_null4.__stackDetails = _e;
+  return foobar_null4;
+}();
+exports.foo = foo;
+exports.bar = bar;
+exports.baz = baz;
+exports.foobar = foobar;"
+`;
+
 exports[`babel plugin for file workletization workletizes ArrowFunctionExpression 1`] = `
 "var _worklet_2420910284744_init_data = {
   code: "function null1(){return'bar';}",

packages/react-native-reanimated/__tests__/plugin.test.ts

@@ -2391,6 +2391,36 @@ describe('babel plugin', () => {
       expect(code).not.toHaveWorkletData();
       expect(code).toMatchSnapshot();
     });
+
+    it('moves CommonJS export to the bottom of the file', () => {
+      const input = html`<script>
+        'worklet';
+        exports.foo = foo;
+        function foo() {}
+        const bar = 1;
+      </script>`;
+
+      const { code } = runPlugin(input);
+      expect(code).toContain('var bar = 1;\nexports.foo = foo;');
+      expect(code).toMatchSnapshot();
+    });
+
+    it('moves multiple CommonJS exports to the bottom of the file', () => {
+      const input = html`<script>
+        'worklet';
+        exports.foo = foo;
+        exports.bar = bar;
+        function foo() {}
+        function bar() {}
+        function baz() {}
+        exports.baz = baz;
+        exports.foobar = foobar;
+        function foobar() {}
+      </script>`;
+
+      const { code } = runPlugin(input);
+      expect(code).toMatchSnapshot();
+    });
   });
 
   describe('for context objects', () => {

packages/react-native-reanimated/plugin/src/file.ts

@@ -5,8 +5,11 @@ import {
   directive,
   directiveLiteral,
   identifier,
+  isAssignmentExpression,
   isBlockStatement,
+  isExpressionStatement,
   isIdentifier,
+  isMemberExpression,
   isObjectProperty,
   objectProperty,
   returnStatement,
@@ -57,6 +60,7 @@ export function processIfWorkletFile(
  */
 function processWorkletFile(programPath: NodePath<Program>) {
   const statements = programPath.get('body');
+  dehoistCommonJSExports(programPath.node);
   statements.forEach((statement) => {
     const candidatePath = getCandidate(statement);
     processWorkletizableEntity(candidatePath);
@@ -189,3 +193,32 @@ function appendWorkletClassMarker(classBody: ClassBody) {
     classProperty(identifier('__workletClass'), booleanLiteral(true))
   );
 }
+
+function dehoistCommonJSExports(program: Program) {
+  const statements = program.body;
+  let end = statements.length;
+  let current = 0;
+
+  while (current < end) {
+    const statement = statements[current];
+    if (!isCommonJSExport(statement)) {
+      current++;
+      continue;
+    }
+    const exportStatement = statements.splice(current, 1);
+    statements.push(...exportStatement);
+    // We just removed one element from non-processed part,
+    // so we need to decrement the end index but not the current index.
+    end--;
+  }
+}
+
+function isCommonJSExport(statement: Statement) {
+  return (
+    isExpressionStatement(statement) &&
+    isAssignmentExpression(statement.expression) &&
+    isMemberExpression(statement.expression.left) &&
+    isIdentifier(statement.expression.left.object) &&
+    statement.expression.left.object.name === 'exports'
+  );
+}