fix: caller.polyfillMethod as 'false' should work

ntucker · Feb 17, 2025 · ce1417a · ce1417a
1 parent 1b695de
commit ce1417a
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Showing 2 changed files with 12 additions and 2 deletions.
diff --git a/packages/babel-preset-anansi/index.js b/packages/babel-preset-anansi/index.js
@@ -76,10 +76,10 @@ function buildPreset(api, options = {}) {
   if (process.env.BABEL_MODULES) {
     options.modules = process.env.BABEL_MODULES;
   }
-  if (api.caller(caller => caller && caller.polyfillMethod)) {
+  if (api.caller(caller => caller && caller.polyfillMethod) !== undefined) {
     options.polyfillMethod = api.caller(caller => caller.polyfillMethod);
   }
-  if (process.env.BABEL_POLYFILL_METHOD) {
+  if (process.env.BABEL_POLYFILL_METHOD !== undefined) {
     options.polyfillMethod = process.env.BABEL_POLYFILL_METHOD;
   }
   const shouldHotReload =

diff --git a/packages/babel-preset-anansi/transform2018.test.js b/packages/babel-preset-anansi/transform2018.test.js
@@ -180,6 +180,16 @@ describe('buildPreset - Babel Transform', () => {
     expect(transformedCode).toMatchSnapshot();
   });
 
+  it('should use @babel/runtime by default when caller sets polyfillMethod to false', () => {
+    api.env.mockReturnValue('development');
+    process.env.NODE_ENV = 'development';
+    api.caller.mockImplementation(cb => cb({ polyfillMethod: false }));
+    const code = `class MyClass { declare myThing; myProp: number = 42; }console.log(Object.hasOwn({ a: 1 }, 'a') ? 'yes' : 'no');`;
+    let transformedCode = transformCode(code, { loose: false });
+    expect(transformedCode).not.toContain('core-js');
+    expect(transformedCode).toContain('@babel/runtime/');
+  });
+
   it('should use core-js-pure by default when caller is rollup', () => {
     api.env.mockReturnValue('development');
     process.env.NODE_ENV = 'development';