feat(dist-custom-elements-bundle): add deprecation warning (#3167)

in preparation to deprecate the `dist-custom-elements-bundle` output
target, fire a warning when the build process begins if the output target
is found in a user's `stencil.config.ts`

src/compiler/config/outputs/index.ts

@@ -1,6 +1,6 @@
 import type * as d from '../../../declarations';
-import { buildError } from '@utils';
-import { VALID_TYPES } from '../../output-targets/output-utils';
+import { buildError, buildWarn } from '@utils';
+import { DIST_CUSTOM_ELEMENTS_BUNDLE, VALID_TYPES } from '../../output-targets/output-utils';
 import { validateCollection } from './validate-collection';
 import { validateCustomElement } from './validate-custom-element';
 import { validateCustomOutput } from './validate-custom-output';
@@ -22,6 +22,10 @@ export const validateOutputTargets = (config: d.Config, diagnostics: d.Diagnosti
       err.messageText = `Invalid outputTarget type "${
         outputTarget.type
       }". Valid outputTarget types include: ${VALID_TYPES.map((t) => `"${t}"`).join(', ')}`;
+    } else if (outputTarget.type === DIST_CUSTOM_ELEMENTS_BUNDLE) {
+      // TODO(STENCIL-260): Remove this check when the 'dist-custom-elements-bundle' is removed
+      const warning = buildWarn(diagnostics);
+      warning.messageText = `dist-custom-elements-bundle is deprecated and will be removed in a future major version release. Use "dist-custom-elements" instead. If "dist-custom-elements" does not meet your needs, please add a comment to https://github.com/ionic-team/stencil/issues/3136.`;
     }
   });
 

src/compiler/config/test/validate-config.spec.ts

@@ -312,6 +312,19 @@ describe('validation', () => {
     expect(validated.diagnostics).toHaveLength(1);
   });
 
+  it('should warn when dist-custom-elements-bundle is found', () => {
+    userConfig.outputTargets = [
+      {
+        type: 'dist-custom-elements-bundle',
+      },
+    ];
+    const validated = validateConfig(userConfig);
+    expect(validated.diagnostics).toHaveLength(1);
+    expect(validated.diagnostics[0].messageText).toBe(
+      'dist-custom-elements-bundle is deprecated and will be removed in a future major version release. Use "dist-custom-elements" instead. If "dist-custom-elements" does not meet your needs, please add a comment to https://github.com/ionic-team/stencil/issues/3136.'
+    );
+  });
+
   it('should default outputTargets with www', () => {
     const { config } = validateConfig(userConfig);
     expect(config.outputTargets.some((o) => o.type === 'www')).toBe(true);