Load Markdown and XML parsers on demand (fixes #33141)

extensions/extension-editing/src/extensionLinter.ts

@@ -8,8 +8,7 @@ import * as path from 'path';
 
 import { parseTree, findNodeAtLocation, Node as JsonNode } from 'jsonc-parser';
 import * as nls from 'vscode-nls';
-import * as MarkdownIt from 'markdown-it';
-import * as parse5 from 'parse5';
+import * as MarkdownItType from 'markdown-it';
 
 import { languages, workspace, Disposable, ExtensionContext, TextDocument, Uri, Diagnostic, Range, DiagnosticSeverity, Position } from 'vscode';
 
@@ -33,7 +32,7 @@ enum Context {
 }
 
 interface TokenAndPosition {
-	token: MarkdownIt.Token;
+	token: MarkdownItType.Token;
 	begin: number;
 	end: number;
 }
@@ -53,7 +52,7 @@ export class ExtensionLinter {
 	private packageJsonQ = new Set<TextDocument>();
 	private readmeQ = new Set<TextDocument>();
 	private timer: NodeJS.Timer;
-	private markdownIt = new MarkdownIt();
+	private markdownIt: MarkdownItType.MarkdownIt;
 
 	constructor(private context: ExtensionContext) {
 		this.disposables.push(
@@ -148,8 +147,11 @@ export class ExtensionLinter {
 			}
 
 			const text = document.getText();
+			if (!this.markdownIt) {
+				this.markdownIt = new (await import('markdown-it'));
+			}
 			const tokens = this.markdownIt.parse(text, {});
-			const tokensAndPositions = (function toTokensAndPositions(this: ExtensionLinter, tokens: MarkdownIt.Token[], begin = 0, end = text.length): TokenAndPosition[] {
+			const tokensAndPositions = (function toTokensAndPositions(this: ExtensionLinter, tokens: MarkdownItType.Token[], begin = 0, end = text.length): TokenAndPosition[] {
 				const tokensAndPositions = tokens.map<TokenAndPosition>(token => {
 					if (token.map) {
 						const tokenBegin = document.offsetAt(new Position(token.map[0], 0));
@@ -192,8 +194,9 @@ export class ExtensionLinter {
 				});
 
 			let svgStart: Diagnostic;
-			tokensAndPositions.filter(tnp => tnp.token.type === 'text' && tnp.token.content)
-				.map(tnp => {
+			for (const tnp of tokensAndPositions) {
+				if (tnp.token.type === 'text' && tnp.token.content) {
+					const parse5 = await import('parse5');
 					const parser = new parse5.SAXParser({ locationInfo: true });
 					parser.on('startTag', (name, attrs, selfClosing, location) => {
 						if (name === 'img') {
@@ -220,13 +223,14 @@ export class ExtensionLinter {
 					});
 					parser.write(tnp.token.content);
 					parser.end();
-				});
+				}
+			}
 
 			this.diagnosticsCollection.set(document.uri, diagnostics);
 		};
 	}
 
-	private locateToken(text: string, begin: number, end: number, token: MarkdownIt.Token, content: string) {
+	private locateToken(text: string, begin: number, end: number, token: MarkdownItType.Token, content: string) {
 		if (content) {
 			const tokenBegin = text.indexOf(content, begin);
 			if (tokenBegin !== -1) {