feat(challenge33): add new challenge about decoupling

libs/decoupling/brain/src/index.ts

@@ -0,0 +1,4 @@
+export {
+  BtnDisabledDirective,
+  ButtonState,
+} from './lib/button-disabled.directive';

libs/decoupling/brain/src/lib/button-disabled.directive.ts

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+/* eslint-disable @angular-eslint/directive-selector */
+/* eslint-disable @angular-eslint/no-host-metadata-property */
+import { Directive, WritableSignal, signal } from '@angular/core';
+
+export type ButtonState = 'enabled' | 'disabled';
+
+@Directive({
+  selector: 'button[btnDisabled]',
+  standalone: true,
+  host: {
+    '(click)': 'toggleState()',
+  },
+})
+export class BtnDisabledDirective {
+  state: WritableSignal<ButtonState> = signal('enabled');
+
+  toggleState() {
+    this.state.set(this.state() === 'enabled' ? 'disabled' : 'enabled');
+  }
+}

libs/decoupling/brain/src/test-setup.ts

@@ -0,0 +1,8 @@
+// @ts-expect-error https://thymikee.github.io/jest-preset-angular/docs/getting-started/test-environment
+globalThis.ngJest = {
+  testEnvironmentOptions: {
+    errorOnUnknownElements: true,
+    errorOnUnknownProperties: true,
+  },
+};
+import 'jest-preset-angular/setup-jest';