[html] resolve JS completion proposals

extensions/html/server/src/utils/words.ts

@@ -0,0 +1,35 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+export function getWordAtText(text: string, offset: number, wordDefinition: RegExp): { start: number, length: number } {
+	let lineStart = offset;
+	while (lineStart > 0 && !isNewlineCharacter(text.charCodeAt(lineStart - 1))) {
+		lineStart--;
+	}
+	let offsetInLine = offset - lineStart;
+	let lineText = text.substr(lineStart);
+
+	// make a copy of the regex as to not keep the state
+	let flags = wordDefinition.ignoreCase ? 'gi' : 'g';
+	wordDefinition = new RegExp(wordDefinition.source, flags);
+
+	let match = wordDefinition.exec(lineText);
+	while (match && match.index + match[0].length < offsetInLine) {
+		match = wordDefinition.exec(lineText);
+	}
+	if (match && match.index <= offsetInLine) {
+		return { start: match.index + lineStart, length: match[0].length };
+	}
+
+	return { start: offset, length: 0 };
+}
+
+
+const CR = '\r'.charCodeAt(0);
+const NL = '\n'.charCodeAt(0);
+function isNewlineCharacter(charCode: number) {
+	return charCode === CR || charCode === NL;
+}