fix(shaker): process functions and classes definitions in default exp…

…orts (fixes #1308) (#1343)

* feat(babel): overrideContext option

* fix(shaker): process functions and classes definitions in default exports

.changeset/lovely-moles-laugh.md

@@ -0,0 +1,5 @@
+---
+'@linaria/babel-preset': patch
+---
+
+The new option, 'overrideContext,' allows the extension of the module evaluation context.

.changeset/plenty-mice-fry.md

@@ -0,0 +1,8 @@
+---
+'@linaria/babel-preset': patch
+'@linaria/shaker': patch
+'@linaria/testkit': patch
+'@linaria/utils': patch
+---
+
+Fixes error with $RefreshReg$ in webpack and resolves the issue with the shaker when default export is a function or class definition.

packages/shaker/src/plugins/__tests__/__snapshots__/shaker-plugin.test.ts.snap

@@ -50,6 +50,12 @@ exports[`shaker should keep side-effects from modules 1`] = `
 export const a = 1;"
 `;
 
+exports[`shaker should not remove referenced export 1`] = `
+"export default class Media {}
+const _c = Media;
+export const __linariaPreval = {};"
+`;
+
 exports[`shaker should process array patterns 1`] = `
 "const [,, c] = array;
 export { c };"

packages/shaker/src/plugins/__tests__/shaker-plugin.test.ts

@@ -435,4 +435,16 @@ describe('shaker', () => {
     expect(code).toMatchSnapshot();
     expect(metadata.imports.size).toBe(0);
   });
+
+  it('should not remove referenced export', () => {
+    const { code, metadata } = keep(['__linariaPreval'])`
+      export default class Media {
+      }
+      const _c = Media;
+      export const __linariaPreval = {};
+    `;
+
+    expect(code).toMatchSnapshot();
+    expect(metadata.imports.size).toBe(0);
+  });
 });

packages/shaker/src/plugins/shaker-plugin.ts

@@ -59,6 +59,10 @@ function getBindingForExport(exportPath: NodePath): Binding | undefined {
     }
   }
 
+  if (exportPath.isFunctionDeclaration() || exportPath.isClassDeclaration()) {
+    return exportPath.scope.getBinding(exportPath.node.id!.name);
+  }
+
   return undefined;
 }
 

packages/utils/src/removeDangerousCode.ts

@@ -17,6 +17,7 @@ const isGlobal = (id: NodePath<Identifier>): boolean => {
 };
 
 const forbiddenGlobals = new Set([
+  '$RefreshReg$',
   'XMLHttpRequest',
   'clearImmediate',
   'clearInterval',