refactor(typescript): syntax only service context isolation

packages/typescript/lib/plugins/syntactic.ts

@@ -12,7 +12,39 @@ import {
 	convertOutliningSpan,
 	convertTextChange
 } from '../utils/lspConverters';
-import { getLanguageService } from '../syntacticLanguageService';
+import { createSyntaxOnlyService } from '../syntaxOnlyService';
+import type * as ts from 'typescript';
+
+const snapshots = new WeakMap<TextDocument, [number, ts.IScriptSnapshot]>();
+
+let created: ReturnType<typeof createSyntaxOnlyService> | undefined;
+
+export function getLanguageServiceByDocument(ts: typeof import('typescript'), document: TextDocument) {
+	if (!created) {
+		created = createSyntaxOnlyService(ts, true);
+	}
+	let cache = snapshots.get(document);
+	if (!cache || cache[0] !== document.version) {
+		const snapshot = ts.ScriptSnapshot.fromString(document.getText());
+		cache = [document.version, snapshot];
+		snapshots.set(document, cache);
+		created.updateFile(
+			document.uri,
+			cache[1],
+			document.languageId === 'javascript'
+				? ts.ScriptKind.JS
+				: document.languageId === 'javascriptreact'
+					? ts.ScriptKind.JSX
+					: document.languageId === 'typescriptreact'
+						? ts.ScriptKind.TSX
+						: ts.ScriptKind.TS
+		);
+	}
+	return {
+		languageService: created.languageService,
+		fileName: document.uri,
+	};
+}
 
 export function create(
 	ts: typeof import('typescript'),
@@ -141,17 +173,3 @@ export function create(
 		},
 	};
 }
-
-import type * as ts from 'typescript';
-
-const snapshots = new WeakMap<TextDocument, [number, ts.IScriptSnapshot]>();
-
-export function getLanguageServiceByDocument(ts: typeof import('typescript'), document: TextDocument) {
-	let cache = snapshots.get(document);
-	if (!cache || cache[0] !== document.version) {
-		const snapshot = ts.ScriptSnapshot.fromString(document.getText());
-		cache = [document.version, snapshot];
-		snapshots.set(document, cache);
-	}
-	return getLanguageService(ts, cache[1], document.languageId, true);
-}

packages/typescript/lib/syntaxOnlyService.ts

@@ -0,0 +1,49 @@
+import type * as ts from 'typescript';
+
+export function createSyntaxOnlyService(ts: typeof import('typescript'), syntaxOnly: boolean) {
+	let currentProjectVersion = -1;
+	let fileNames: string[] = [];
+
+	const scriptInfos = new Map<string, {
+		snapshot: ts.IScriptSnapshot;
+		kind: ts.ScriptKind;
+		version: number;
+	}>();
+	const host: ts.LanguageServiceHost = {
+		getProjectVersion: () => currentProjectVersion.toString(),
+		getScriptFileNames: () => fileNames,
+		getScriptVersion: () => currentProjectVersion.toString(),
+		getScriptSnapshot: fileName => scriptInfos.get(fileName)!.snapshot,
+		getScriptKind: fileName => scriptInfos.get(fileName)!.kind,
+		getCompilationSettings: () => ({}),
+		getCurrentDirectory: () => '',
+		getDefaultLibFileName: () => '',
+		readFile: () => undefined,
+		fileExists: fileName => scriptInfos.has(fileName),
+	};
+
+	return {
+		languageService: syntaxOnly
+			? ts.createLanguageService(host, undefined, ts.LanguageServiceMode.Syntactic)
+			: ts.createLanguageService(host),
+		updateFile,
+	};
+
+	function updateFile(fileName: string, snapshot: ts.IScriptSnapshot, scriptKind: ts.ScriptKind) {
+		let scriptInfo = scriptInfos.get(fileName);
+		if (scriptInfo?.snapshot === snapshot && scriptInfo.kind === scriptKind) {
+			return;
+		}
+		currentProjectVersion++;
+		scriptInfo = {
+			snapshot,
+			kind: scriptKind,
+			version: (scriptInfo?.version ?? 0) + 1,
+		};
+		const filesChanged = !scriptInfos.has(fileName);
+		scriptInfos.set(fileName, scriptInfo);
+		if (filesChanged) {
+			fileNames = [...scriptInfos.keys()];
+		}
+	}
+}