feat: decorators

Author: rix0rrr

fixtures/jsii-calc/lib/decorators.ts

@@ -0,0 +1,42 @@
+function classDecorator(x: typeof SomeDecoratedClass, _context: ClassDecoratorContext): typeof SomeDecoratedClass {
+  const ret = class extends x {
+    constructor() {
+      super();
+      this.state = this.state + this.state;
+    }
+  };
+
+  // This adds a field to the class, but we can't reflect that in the type because of the limitations
+  // of decorators. That's we advertise it through interface merging below.
+  ret.prototype['field'] = 'some_added_field';
+
+  return ret;
+}
+
+function methodDecorator<A extends Function>(x: A, _context: ClassMethodDecoratorContext): A {
+  return x;
+}
+
+@classDecorator
+export class SomeDecoratedClass {
+  protected state = 'state';
+
+  @methodDecorator
+  public accessState() {
+    return this.state;
+  }
+}
+
+export interface SomeDecoratedClass {
+  field: string;
+}
+
+/**
+ * Exercise the above code
+ */
+function tryDecoratedClass() {
+  const instance = new SomeDecoratedClass();
+  return instance.field;
+}
+// Suppress unused locals warnings
+void tryDecoratedClass;

fixtures/jsii-calc/lib/index.ts

@@ -9,6 +9,7 @@ export * from './stability';
 export * from './submodules';
 export * from './container-types';
 export * from './indirect-implementation';
+export * from './decorators';
 
 export * as submodule from './submodule';
 export * as onlystatic from './only-static';

src/tsconfig/compiler-options.ts

@@ -4,7 +4,6 @@ import * as Case from '../case';
 export const BASE_COMPILER_OPTIONS: ts.CompilerOptions = {
   alwaysStrict: true,
   declaration: true,
-  experimentalDecorators: true,
   incremental: true,
   lib: ['lib.es2020.d.ts'],
   module: ts.ModuleKind.CommonJS,

test/__snapshots__/integration.test.ts.snap

@@ -484,7 +484,6 @@ function expectedTypeScriptConfig() {
       alwaysStrict: true,
       composite: false,
       declaration: true,
-      experimentalDecorators: true,
       incremental: true,
       inlineSourceMap: true,
       inlineSources: true,

test/compiler.test.ts

@@ -235,3 +235,4 @@ describe('Object Validator', () => {
 function anythingExceptUndefined() {
   return fc.anything().filter((x) => x !== undefined);
 }
+