feat: top-level return

app/swcx/sandbox.js

@@ -10,6 +10,7 @@ import {
   isIdentifier,
   isIfStatement,
   isObjectPattern,
+  isReturnStatement,
   isVariableDeclarator,
   isWhileStatement,
 } from '@/swcx/types.js';
@@ -206,7 +207,10 @@ export default class Sandbox {
         if (!child) {
           continue;
         }
-        yield* this.execute(child, node);
+        const result = yield* this.execute(child, node);
+        if (result) {
+          return result;
+        }
       }
       // Loops...
       if (isForStatement(node)) {
@@ -230,6 +234,10 @@ export default class Sandbox {
         }
       }
     } while (loop);
+    // Top-level return.
+    if (isReturnStatement(node)) {
+      return !node.argument ? {value: undefined} : this.evaluate(node.argument);
+    }
     if (isExpressionStatement(node)) {
       yield this.evaluate(node.expression);
     }

app/swcx/sandbox.test.js

@@ -151,7 +151,7 @@ test('evaluates loops', async () => {
     });
 });
 
-test('retuns undefined for nonexistent variables in scope', async () => {
+test('evaluates undefined for nonexistent variables in scope', async () => {
   const sandbox = new Sandbox(
     await parse(`
       const x = y
@@ -164,6 +164,36 @@ test('retuns undefined for nonexistent variables in scope', async () => {
     });
 });
 
+test('returns values at the top level', async () => {
+  let sandbox;
+  sandbox = new Sandbox(
+    await parse(`
+      x = 16
+      y = 4
+      return [x * 3, y * 3]
+      x = 32
+      y = 8
+    `, {allowReturnOutsideFunction: true}),
+  );
+  const {value: {value}} = sandbox.run();
+  expect(value)
+    .to.deep.equal([48, 12]);
+  expect(sandbox.context)
+    .to.deep.equal({x: 16, y: 4});
+  sandbox = new Sandbox(
+    await parse(`
+      x = 16
+      y = 4
+      return
+      x = 32
+      y = 8
+    `, {allowReturnOutsideFunction: true}),
+  );
+  sandbox.run();
+  expect(sandbox.context)
+    .to.deep.equal({x: 16, y: 4});
+});
+
 test('sets variables in global scope', async () => {
   const sandbox = new Sandbox(
     await parse(`

app/swcx/traverse.js

@@ -29,6 +29,7 @@ export const TRAVERSAL_PATH = {
   OptionalChainingExpression: ['base'],
   ParenthesisExpression: ['expression'],
   RegExpLiteral: [],
+  ReturnStatement: ['argument'],
   StringLiteral: [],
   UnaryExpression: ['argument'],
   UpdateExpression: ['argument'],

app/swcx/types.js

@@ -92,6 +92,14 @@ export function isObjectPattern(node) {
   return true;
 }
 
+export function isReturnStatement(node) {
+  /* v8 ignore next 3 */
+  if (!node || node.type !== 'ReturnStatement') {
+    return false;
+  }
+  return true;
+}
+
 export function isSpreadElement(node) {
   /* v8 ignore next 3 */
   if (!node || node.type !== 'SpreadElement') {