feat: allow free function exports in typewriter (#1379)

Typewriter does not allow free functions to be exported today. This PR enables exporting free functions. Required for aws/aws-cdk#31850. --------- Signed-off-by: github-actions <[email protected]> Co-authored-by: github-actions <[email protected]> Co-authored-by: Momo Kornher <[email protected]>
cdklabs · Oct 25, 2024 · 83ec1c3 · 83ec1c3
1 parent 12bebf9
commit 83ec1c3
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Showing 4 changed files with 58 additions and 7 deletions.
diff --git a/packages/@cdklabs/typewriter/src/callable.ts b/packages/@cdklabs/typewriter/src/callable.ts
@@ -6,7 +6,7 @@ import { Statement } from './statements';
 import { Block } from './statements/block';
 import { asStmt } from './statements/private';
 import { Type } from './type';
-import { DeclarationKind, TypeDeclaration, TypeSpec } from './type-declaration';
+import { DeclarationKind, Exported, TypeDeclaration, TypeSpec } from './type-declaration';
 
 export interface CallableSpec extends TypeSpec {
   name: string;
@@ -29,7 +29,7 @@ export interface CallableExpr {
 /**
  * Can't be called "Function"
  */
-export class FreeFunction extends TypeDeclaration implements CallableDeclaration {
+export class FreeFunction extends TypeDeclaration implements CallableDeclaration, Exported {
   public readonly returnType: Type;
   public readonly kind = DeclarationKind.Function;
   public readonly parameters = new Array<Parameter>();

diff --git a/packages/@cdklabs/typewriter/src/renderer/typescript.ts b/packages/@cdklabs/typewriter/src/renderer/typescript.ts
@@ -55,7 +55,7 @@ import {
 import { StructType } from '../struct';
 import { ThingSymbol } from '../symbol';
 import { PrimitiveType, Type } from '../type';
-import { TypeParameterSpec } from '../type-declaration';
+import { Exported, TypeParameterSpec } from '../type-declaration';
 import { Initializer, MemberVisibility, Method } from '../type-member';
 
 /**
@@ -431,11 +431,10 @@ 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 & Exported) {
     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(': ');

diff --git a/packages/@cdklabs/typewriter/src/type-declaration.ts b/packages/@cdklabs/typewriter/src/type-declaration.ts
@@ -19,6 +19,10 @@ export interface Exportable {
   export?: boolean;
 }
 
+export interface Exported {
+  exported?: boolean;
+}
+
 export interface TypeParameterSpec {
   readonly name: string;
   readonly extendsType?: Type;
@@ -52,7 +56,7 @@ export interface TypeSpec extends Documented, Exportable {
 /**
  * An abstract jsii type
  */
-export abstract class TypeDeclaration implements Documented {
+export abstract class TypeDeclaration implements Documented, Exported {
   /**
    * The simple name of the type (MyClass).
    */

diff --git a/packages/@cdklabs/typewriter/test/exports.test.ts b/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;"
+    `);
+  });
+});