feat: allow free function exports in typewriter

packages/@cdklabs/typewriter/src/renderer/typescript.ts

@@ -54,7 +54,7 @@ import {
 import { StructType } from '../struct';
 import { ThingSymbol } from '../symbol';
 import { PrimitiveType, Type } from '../type';
-import { TypeParameterSpec } from '../type-declaration';
+import { TypeDeclaration, TypeParameterSpec } from '../type-declaration';
 import { Initializer, MemberVisibility, Method } from '../type-member';
 
 export class TypeScriptRenderer extends Renderer {
@@ -411,11 +411,10 @@ export class TypeScriptRenderer extends Renderer {
     throw new Error(`Symbol ${sym} (in ${sym.scope}) not visible from ${this.scopes[0]} (missing import?)`);
   }
 
-  protected renderFunction(func: CallableDeclaration) {
+  protected renderFunction(func: CallableDeclaration & TypeDeclaration) {
     this.renderDocs(func);
     this.emit(`// @ts-ignore TS6133\n`);
-
-    this.emit(`function ${func.name}`);
+    this.emit(`${func.exported ? 'export ' : ''}function ${func.name}`);
     this.renderParameters(func.parameters);
     if (func.returnType) {
       this.emit(': ');

packages/@cdklabs/typewriter/test/exports.test.ts

@@ -0,0 +1,48 @@
+import { FreeFunction, Module, TypeScriptRenderer } from '../src';
+
+const renderer = new TypeScriptRenderer();
+let scope: Module;
+
+beforeEach(() => {
+  scope = new Module('typewriter.test');
+});
+
+describe('functions', () => {
+  test('functions are implicitly not exported', () => {
+    new FreeFunction(scope, {
+      name: 'freeFunction',
+    });
+
+    expect(renderer.render(scope)).toMatchInlineSnapshot(`
+      "/* eslint-disable prettier/prettier,max-len */
+      // @ts-ignore TS6133
+      function freeFunction(): void;"
+    `);
+  });
+
+  test('functions can be explicitly exported', () => {
+    new FreeFunction(scope, {
+      name: 'freeFunction',
+      export: true,
+    });
+
+    expect(renderer.render(scope)).toMatchInlineSnapshot(`
+      "/* eslint-disable prettier/prettier,max-len */
+      // @ts-ignore TS6133
+      export function freeFunction(): void;"
+    `);
+  });
+
+  test('functions can be explicitly not exported', () => {
+    new FreeFunction(scope, {
+      name: 'freeFunction',
+      export: false,
+    });
+
+    expect(renderer.render(scope)).toMatchInlineSnapshot(`
+      "/* eslint-disable prettier/prettier,max-len */
+      // @ts-ignore TS6133
+      function freeFunction(): void;"
+    `);
+  });
+});