Merge commit 'be3e8236086165e5e45a5a10783823874b3f3ebd' as 'lib/vscode'

lib/vscode/extensions/markdown-language-features/src/slugify.ts

@@ -0,0 +1,32 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+export class Slug {
+	public constructor(
+		public readonly value: string
+	) { }
+
+	public equals(other: Slug): boolean {
+		return this.value === other.value;
+	}
+}
+
+export interface Slugifier {
+	fromHeading(heading: string): Slug;
+}
+
+export const githubSlugifier: Slugifier = new class implements Slugifier {
+	fromHeading(heading: string): Slug {
+		const slugifiedHeading = encodeURI(
+			heading.trim()
+				.toLowerCase()
+				.replace(/\s+/g, '-') // Replace whitespace with -
+				.replace(/[\]\[\!\'\#\$\%\&\(\)\*\+\,\.\/\:\;\<\=\>\?\@\\\^\_\{\|\}\~\`。，、；：？！…—·ˉ¨‘’“”々～‖∶＂＇｀｜〃〔〕〈〉《》「」『』．〖〗【】（）［］｛｝]/g, '') // Remove known punctuators
+				.replace(/^\-+/, '') // Remove leading -
+				.replace(/\-+$/, '') // Remove trailing -
+		);
+		return new Slug(slugifiedHeading);
+	}
+};