feat(compiler): add defineCustomElements method & signature typedef

src/compiler/output-targets/dist-custom-elements/custom-elements-types.ts

@@ -44,6 +44,7 @@ const generateCustomElementsTypesOutput = async (
   outputTarget: d.OutputTargetDistCustomElements
 ) => {
   const isBarrelExport = outputTarget.customElementsExportBehavior === 'single-export-module';
+  const isBundleExport = outputTarget.customElementsExportBehavior === 'bundle';
 
   // the path where we're going to write the typedef for the whole dist-custom-elements output
   const customElementsDtsPath = join(outputTarget.dir!, 'index.d.ts');
@@ -97,6 +98,22 @@ const generateCustomElementsTypesOutput = async (
     `  rel?: (el: EventTarget, eventName: string, listener: EventListenerOrEventListenerObject, options: boolean | AddEventListenerOptions) => void;`,
     `}`,
     `export declare const setPlatformOptions: (opts: SetPlatformOptions) => void;`,
+    ...(isBundleExport
+      ? [
+          ``,
+          `/**`,
+          ` * Utility to define all custom elements within this package using the tag name provided in the component's source.`,
+          ` * When defining each custom element, it will also check it's safe to define by:`,
+          ` *`,
+          ` * 1. Ensuring the "customElements" registry is available in the global context (window).`,
+          ` * 2. Ensuring that the component tag name is not already defined.`,
+          ` *`,
+          ` * Use the standard [customElements.define()](https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry/define)`,
+          ` * method instead to define custom elements individually, or to provide a different tag name.`,
+          ` */`,
+          `export declare const defineCustomElements: (opts?: any) => void;`,
+        ]
+      : []),
   ];
 
   const componentsDtsRelPath = relDts(outputTarget.dir!, join(typesDir, 'components.d.ts'));

src/compiler/output-targets/dist-custom-elements/index.ts

@@ -87,9 +87,7 @@ export const getBundleOptions = (
     // @see {@link https://rollupjs.org/guide/en/#conventions} for more info.
     index: '\0core',
   },
-  loader: {
-    '\0core': generateEntryPoint(outputTarget),
-  },
+  loader: {},
   inlineDynamicImports: outputTarget.inlineDynamicImports,
   preserveEntrySignatures: 'allow-extension',
 });
@@ -189,8 +187,13 @@ export const addCustomElementInputs = (
   outputTarget: d.OutputTargetDistCustomElements
 ): void => {
   const components = buildCtx.components;
-  // an array to store the imports of these modules that we're going to add to our entry chunk
+  // An array to store the imports of these modules that we're going to add to our entry chunk
   const indexImports: string[] = [];
+  // An array to store the export declarations that we're going to add to our entry chunk
+  const indexExports: string[] = [];
+  // An array to store the exported component names that will be used for the `defineCustomElements`
+  // function on the `bundle` export behavior option
+  const exportNames: string[] = [];
 
   components.forEach((cmp) => {
     const exp: string[] = [];
@@ -201,7 +204,7 @@ export const addCustomElementInputs = (
 
     if (cmp.isPlain) {
       exp.push(`export { ${importName} as ${exportName} } from '${cmp.sourceFilePath}';`);
-      indexImports.push(`export { {${exportName} } from '${coreKey}';`);
+      indexExports.push(`export { {${exportName} } from '${coreKey}';`);
     } else {
       // the `importName` may collide with the `exportName`, alias it just in case it does with `importAs`
       exp.push(
@@ -216,39 +219,88 @@ export const addCustomElementInputs = (
       // correct virtual module, if we instead referenced, for instance,
       // `cmp.sourceFilePath`, we would end up with duplicated modules in our
       // output.
-      indexImports.push(
+      indexExports.push(
         `export { ${exportName}, defineCustomElement as defineCustomElement${exportName} } from '${coreKey}';`
       );
     }
 
+    indexImports.push(`import { ${exportName} } from '${coreKey}';`);
+    exportNames.push(exportName);
+
     bundleOpts.inputs[cmp.tagName] = coreKey;
     bundleOpts.loader![coreKey] = exp.join('\n');
   });
 
-  // Only re-export component definitions if the barrel export behavior is set
-  if (outputTarget.customElementsExportBehavior === 'single-export-module') {
-    bundleOpts.loader!['\0core'] += indexImports.join('\n');
-  }
+  // Generate the contents of the entry file to be created by the bundler
+  bundleOpts.loader!['\0core'] = generateEntryPoint(outputTarget, indexImports, indexExports, exportNames);
 };
 
 /**
  * Generate the entrypoint (`index.ts` file) contents for the `dist-custom-elements` output target
  * @param outputTarget the output target's configuration
+ * @param cmpImports The import declarations for local component modules.
+ * @param cmpExports The export declarations for local component modules.
+ * @param cmpNames The exported component names (could be aliased) from local component modules.
  * @returns the stringified contents to be placed in the entrypoint
  */
-export const generateEntryPoint = (outputTarget: d.OutputTargetDistCustomElements): string => {
-  const imp: string[] = [];
+export const generateEntryPoint = (
+  outputTarget: d.OutputTargetDistCustomElements,
+  cmpImports: string[] = [],
+  cmpExports: string[] = [],
+  cmpNames: string[] = []
+): string => {
+  const body: string[] = [];
+  const imports: string[] = [];
+  const exports: string[] = [];
 
-  imp.push(
+  // Exports that are always present
+  exports.push(
     `export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';`,
     `export * from '${USER_INDEX_ENTRY_ID}';`
   );
 
+  // Content related to global scripts
   if (outputTarget.includeGlobalScripts !== false) {
-    imp.push(`import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';`, `globalScripts();`);
+    imports.push(`import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';`);
+    body.push(`globalScripts();`);
+  }
+
+  // Content related to the `bundle` export behavior
+  if (outputTarget.customElementsExportBehavior === 'bundle') {
+    imports.push(...cmpImports);
+    body.push(
+      'export const defineCustomElements = (opts) => {',
+      "    if (typeof customElements !== 'undefined') {",
+      '        [',
+      ...cmpNames.map((cmp) => `            ${cmp},`),
+      '        ].forEach(cmp => {',
+      '            if (!customElements.get(cmp.is)) {',
+      '                customElements.define(cmp.is, cmp, opts);',
+      '            }',
+      '        });',
+      '    }',
+      '};'
+    );
   }
 
-  return imp.join('\n') + '\n';
+  // Content related to the `single-export-module` export behavior
+  if (outputTarget.customElementsExportBehavior === 'single-export-module') {
+    exports.push(...cmpExports);
+  }
+
+  // Generate the contents of the file based on the parts
+  // defined above. This keeps the file structure consistent as
+  // new export behaviors may be added
+  let content = '';
+
+  // Add imports to file content
+  content += imports.length ? imports.join('\n') + '\n' : '';
+  // Add exports to file content
+  content += exports.length ? exports.join('\n') + '\n' : '';
+  // Add body to file content
+  content += body.length ? '\n' + body.join('\n') + '\n' : '';
+
+  return content;
 };
 
 /**

src/compiler/output-targets/test/custom-elements-types.spec.ts

@@ -151,4 +151,63 @@ describe('Custom Elements Typedef generation', () => {
 
     writeFileSpy.mockRestore();
   });
+
+  it('should generate a type signature for the `defineCustomElements` function when `bundle` export behavior is set', async () => {
+    const componentOne = stubComponentCompilerMeta({
+      tagName: 'my-component',
+      sourceFilePath: '/src/components/my-component/my-component.tsx',
+    });
+    const componentTwo = stubComponentCompilerMeta({
+      sourceFilePath: '/src/components/the-other-component/my-real-best-component.tsx',
+      componentClassName: 'MyBestComponent',
+      tagName: 'my-best-component',
+    });
+    const { config, compilerCtx, buildCtx } = setup();
+    (config.outputTargets[0] as d.OutputTargetDistCustomElements).customElementsExportBehavior = 'bundle';
+    buildCtx.components = [componentOne, componentTwo];
+
+    const writeFileSpy = jest.spyOn(compilerCtx.fs, 'writeFile');
+
+    await generateCustomElementsTypes(config, compilerCtx, buildCtx, 'types_dir');
+
+    const expectedTypedefOutput = [
+      '/**',
+      ' * Used to manually set the base path where assets can be found.',
+      ' * If the script is used as "module", it\'s recommended to use "import.meta.url",',
+      ' * such as "setAssetPath(import.meta.url)". Other options include',
+      ' * "setAssetPath(document.currentScript.src)", or using a bundler\'s replace plugin to',
+      ' * dynamically set the path at build time, such as "setAssetPath(process.env.ASSET_PATH)".',
+      ' * But do note that this configuration depends on how your script is bundled, or lack of',
+      ' * bundling, and where your assets can be loaded from. Additionally custom bundling',
+      ' * will have to ensure the static assets are copied to its build directory.',
+      ' */',
+      'export declare const setAssetPath: (path: string) => void;',
+      '',
+      'export interface SetPlatformOptions {',
+      '  raf?: (c: FrameRequestCallback) => number;',
+      '  ael?: (el: EventTarget, eventName: string, listener: EventListenerOrEventListenerObject, options: boolean | AddEventListenerOptions) => void;',
+      '  rel?: (el: EventTarget, eventName: string, listener: EventListenerOrEventListenerObject, options: boolean | AddEventListenerOptions) => void;',
+      '}',
+      'export declare const setPlatformOptions: (opts: SetPlatformOptions) => void;',
+      '',
+      '/**',
+      ` * Utility to define all custom elements within this package using the tag name provided in the component's source.`,
+      ` * When defining each custom element, it will also check it's safe to define by:`,
+      ' *',
+      ' * 1. Ensuring the "customElements" registry is available in the global context (window).',
+      ' * 2. Ensuring that the component tag name is not already defined.',
+      ' *',
+      ' * Use the standard [customElements.define()](https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry/define)',
+      ' * method instead to define custom elements individually, or to provide a different tag name.',
+      ' */',
+      'export declare const defineCustomElements: (opts?: any) => void;',
+      '',
+    ].join('\n');
+
+    expect(compilerCtx.fs.writeFile).toHaveBeenCalledWith(join('my-best-dir', 'index.d.ts'), expectedTypedefOutput, {
+      outputTargetType: DIST_CUSTOM_ELEMENTS,
+    });
+
+    writeFileSpy.mockRestore();
+  });
 });

src/compiler/output-targets/test/output-targets-dist-custom-elements.spec.ts

@@ -11,14 +11,14 @@ import type * as d from '../../../declarations';
 import { OutputTargetDistCustomElements } from '../../../declarations';
 import { STENCIL_APP_GLOBALS_ID, STENCIL_INTERNAL_CLIENT_ID, USER_INDEX_ENTRY_ID } from '../../bundle/entry-alias-ids';
 import { stubComponentCompilerMeta } from '../../types/tests/ComponentCompilerMeta.stub';
+import * as outputCustomElementsMod from '../dist-custom-elements';
 import {
   addCustomElementInputs,
   bundleCustomElements,
   generateEntryPoint,
   getBundleOptions,
   outputCustomElements,
 } from '../dist-custom-elements';
-import * as outputCustomElementsMod from '../dist-custom-elements';
 // TODO(STENCIL-561): fully delete dist-custom-elements-bundle code
 import { DIST_CUSTOM_ELEMENTS, DIST_CUSTOM_ELEMENTS_BUNDLE } from '../output-utils';
 
@@ -67,13 +67,28 @@ describe('Custom Elements output target', () => {
   });
 
   describe('generateEntryPoint', () => {
-    it.each([true, false])('should include globalScripts if the right option is set', (includeGlobalScripts) => {
+    it('should include global scripts when flag is `true`', () => {
+      const entryPoint = generateEntryPoint({
+        type: DIST_CUSTOM_ELEMENTS,
+        includeGlobalScripts: true,
+      });
+
+      expect(entryPoint).toEqual(`import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
+export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
+export * from '${USER_INDEX_ENTRY_ID}';
+globalScripts();
+`);
+    });
+
+    it('should not include global scripts when flag is `false`', () => {
       const entryPoint = generateEntryPoint({
         type: DIST_CUSTOM_ELEMENTS,
-        includeGlobalScripts,
+        includeGlobalScripts: false,
       });
-      const globalScriptsBoilerplate = `import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';\nglobalScripts();`;
-      expect(entryPoint.includes(globalScriptsBoilerplate)).toBe(includeGlobalScripts);
+
+      expect(entryPoint).toEqual(`export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
+export * from '${USER_INDEX_ENTRY_ID}';
+`);
     });
   });
 
@@ -87,9 +102,7 @@ describe('Custom Elements output target', () => {
       expect(options.inputs).toEqual({
         index: '\0core',
       });
-      expect(options.loader).toEqual({
-        '\0core': generateEntryPoint({ type: DIST_CUSTOM_ELEMENTS }),
-      });
+      expect(options.loader).toEqual({});
       expect(options.preserveEntrySignatures).toEqual('allow-extension');
     });
 
@@ -158,9 +171,9 @@ describe('Custom Elements output target', () => {
         );
         addCustomElementInputs(buildCtx, bundleOptions, config.outputTargets[0] as OutputTargetDistCustomElements);
         expect(bundleOptions.loader['\0core']).toEqual(
-          `export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
+          `import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
+export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
 export * from '${USER_INDEX_ENTRY_ID}';
-import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
 globalScripts();
 `
         );
@@ -190,12 +203,13 @@ globalScripts();
         );
         addCustomElementInputs(buildCtx, bundleOptions, config.outputTargets[0] as OutputTargetDistCustomElements);
         expect(bundleOptions.loader['\0core']).toEqual(
-          `export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
+          `import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
+export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
 export * from '${USER_INDEX_ENTRY_ID}';
-import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
-globalScripts();
 export { StubCmp, defineCustomElement as defineCustomElementStubCmp } from '\0StubCmp';
-export { MyBestComponent, defineCustomElement as defineCustomElementMyBestComponent } from '\0MyBestComponent';`
+export { MyBestComponent, defineCustomElement as defineCustomElementMyBestComponent } from '\0MyBestComponent';
+globalScripts();
+`
         );
       });
 
@@ -215,11 +229,57 @@ export { MyBestComponent, defineCustomElement as defineCustomElementMyBestCompon
         );
         addCustomElementInputs(buildCtx, bundleOptions, config.outputTargets[0] as OutputTargetDistCustomElements);
         expect(bundleOptions.loader['\0core']).toEqual(
-          `export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
+          `import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
+export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
 export * from '${USER_INDEX_ENTRY_ID}';
-import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
+export { ComponentWithJsx, defineCustomElement as defineCustomElementComponentWithJsx } from '\0ComponentWithJsx';
 globalScripts();
-export { ComponentWithJsx, defineCustomElement as defineCustomElementComponentWithJsx } from '\0ComponentWithJsx';`
+`
+        );
+      });
+    });
+
+    describe('CustomElementsExportBehavior.BUNDLE', () => {
+      beforeEach(() => {
+        (config.outputTargets[0] as OutputTargetDistCustomElements).customElementsExportBehavior = 'bundle';
+      });
+
+      it('should add a `defineCustomElements` function to the index.js file', () => {
+        const componentOne = stubComponentCompilerMeta();
+        const componentTwo = stubComponentCompilerMeta({
+          componentClassName: 'MyBestComponent',
+          tagName: 'my-best-component',
+        });
+
+        buildCtx.components = [componentOne, componentTwo];
+
+        const bundleOptions = getBundleOptions(
+          config,
+          buildCtx,
+          compilerCtx,
+          config.outputTargets[0] as OutputTargetDistCustomElements
+        );
+        addCustomElementInputs(buildCtx, bundleOptions, config.outputTargets[0] as OutputTargetDistCustomElements);
+        expect(bundleOptions.loader['\0core']).toEqual(
+          `import { globalScripts } from '${STENCIL_APP_GLOBALS_ID}';
+import { StubCmp } from '\0StubCmp';
+import { MyBestComponent } from '\0MyBestComponent';
+export { setAssetPath, setPlatformOptions } from '${STENCIL_INTERNAL_CLIENT_ID}';
+export * from '${USER_INDEX_ENTRY_ID}';
+globalScripts();
+export const defineCustomElements = (opts) => {
+    if (typeof customElements !== 'undefined') {
+        [
+            StubCmp,
+            MyBestComponent,
+        ].forEach(cmp => {
+            if (!customElements.get(cmp.is)) {
+                customElements.define(cmp.is, cmp, opts);
+            }
+        });
+    }
+};
+`
         );
       });
     });

src/declarations/stencil-public-compiler.ts

@@ -2034,11 +2034,14 @@ export interface OutputTargetBaseNext {
  * - `auto-define-custom-elements`: Enables the auto-definition of a component and its children (recursively) in the custom elements registry. This
  * functionality allows consumers to bypass the explicit call to define a component, its children, its children's
  * children, etc. Users of this flag should be aware that enabling this functionality may increase bundle size.
+ * - `bundle`: A `defineCustomElements` function will be exported from the distribution directory. This behavior was added to allow easy migration
+ * from `dist-custom-elements-bundle` to `dist-custom-elements`.
  * - `single-export-module`: All components will be re-exported from the specified directory's root `index.js` file.
  */
 export const CustomElementsExportBehaviorOptions = [
   'default',
   'auto-define-custom-elements',
+  'bundle',
   'single-export-module',
 ] as const;