Add initial custom-element standard snippet

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   slots of the parent element.
 - Autocomplete css custom property names. In use sites, complete to any
   declaration, in declaration sites complete to any declaration or usage.
+- Add autocompletion for standard custom element definition.
 
 ## 2.0.0 - 2017-12-05
 

src/language-server/auto-completer.ts

@@ -23,6 +23,7 @@ import {AttributesSection, AttributeValue, TagName, TextNode} from '../ast-from-
 import AnalyzerLSPConverter from './converter';
 import FeatureFinder, {DatabindingFeature} from './feature-finder';
 import {Handler} from './util';
+import standardSnippets from '../standard-snippets';
 
 
 /**
@@ -114,6 +115,7 @@ export default class AutoCompleter extends Handler {
       if (location.kind === 'attribute') {
         return this.getAttributeCompletions(document, location);
       }
+      return this.getStandardSnippetCompletions();
     }
   }
 
@@ -377,6 +379,13 @@ export default class AutoCompleter extends Handler {
     };
   }
 
+  private getStandardSnippetCompletions(): CompletionList {
+    return {
+      isIncomplete: false,
+      items: standardSnippets
+    };
+  }
+
   private createSortPrefixes(element: Element): Map<string|undefined, string> {
     // A map from the inheritedFrom to a sort prefix. Note that
     // `undefined` is a legal value for inheritedFrom.

src/standard-snippets.ts

@@ -0,0 +1,19 @@
+import {CompletionItemKind, InsertTextFormat} from 'vscode-languageserver';
+
+export default [
+  {
+    label: `custom-element`,
+    documentation: 'Snippet for definition of a custom-element.',
+    insertText:
+`class $1 extends HTMLElement {
+  constructor() {
+    super();
+    $0
+  }
+}
+customElements.define('$2', $1)`,
+    insertTextFormat: InsertTextFormat.Snippet,
+    kind: CompletionItemKind.Class,
+    filterText: 'customelement',
+  }
+];

src/test/auto-completer_test.ts

@@ -19,6 +19,7 @@ import {ResolvedUrl} from 'polymer-analyzer/lib/model/url';
 import {CompletionItem, CompletionItemKind, CompletionList, InsertTextFormat} from 'vscode-languageserver/lib/main';
 
 import {createTestEnvironment} from './util';
+import standardSnippets from '../standard-snippets';
 
 const fixtureDir = path.join(__dirname, '..', '..', 'src', 'test', 'static');
 
@@ -437,7 +438,7 @@ suite('AutoCompleter', () => {
     await client.openFile(indexFile, '<script>\n\n</script>\n' + indexContents);
     const completions =
         await client.getCompletions(indexFile, {line: 1, column: 0});
-    assert.deepEqual(completions, {isIncomplete: true, items: []});
+    assert.deepEqual(completions, {isIncomplete: false, items: standardSnippets});
   });
 
   {