Improve regexp by location parser (check correct group match)

src/providers/angular-html-definition-provider.ts

@@ -14,16 +14,16 @@ export class AngularHtmlDefinitionProvider implements DefinitionProvider {
 
     const regexps = [
       // Interpolation. ex: {{ myProp }}
-      /{{(.*)}}/g,
+      /({{)([^}]+)}}/g,
 
       // Input attributes. ex: [(...)]="myProp"
-      /\[\(?[\w\.\-?]*\)?\]=\"(.*)"/g,
+      /(\[\(?[\w\.\-?]*\)?\]=")([^"]+)"/g,
 
       // Output attributes. ex: (...)="myMethod(...)"
-      /\([\w\.]*\)=\"(.*)\"/g,
+      /(\([\w\.]*\)=")([^"]+)"/g,
 
       // Structural attributes. ex: *ngIf="myProp"
-      /\*\w+=\"(.*)\"/g
+      /(\*\w+=")([^"]+)"/g
     ];
     const expressionMatch: string = utils.parseByLocationRegexps(lineText, position.character, regexps);
     if (!expressionMatch) return null;

src/utils.ts

@@ -1,7 +1,10 @@
 import { Position } from 'vscode';
 
 /**
- * Parse word by regexp and location. Only works with one match group.
+ * Parse text by regexp and position. WARNING: Uses very specific approach..
+ * Should always have TWO side by side match groups.
+ * First group is used to find out second match group position.
+ * Ex. /(\*\w+=\")(.*)\"/g
  * @param text - Text to parse from.
  * @param position - Position used in case of multiple occurrences.
  * @param regexp - Regexp to match.
@@ -10,14 +13,20 @@ export function parseByLocationRegexp(text: string, position: number, regexp: Re
   let propertyName: string = null;
   let match: RegExpMatchArray;
   while (match = regexp.exec(text)) {
+    // This is necessary to avoid infinite loops with zero-width matches
+    if (match.index === regexp.lastIndex) {
+      regexp.lastIndex++;
+    }
+
     // Check if position is in whole regexp match
-    if (match.index <= position && regexp.lastIndex >= position) {
-      // Check if position is in concrete first group match
-      const matchedGroupIndex = match.index + match[0].indexOf(match[1]);
-      const matchedGroupLastIndex = matchedGroupIndex + match[1].length;
-      if (matchedGroupIndex <= position && matchedGroupLastIndex >= position)
-      {
-        propertyName = match[1];
+    if (match.index <= position && regexp.lastIndex >= position && match.length === 3) {
+
+      // Check position of group match
+      const matchedGroupIndex = match.index + match[match.length - 2].length;
+      const matchedGroupLastIndex = matchedGroupIndex + match[match.length - 1].length;
+      if (matchedGroupIndex <= position && matchedGroupLastIndex >= position) {
+        propertyName = match[match.length - 1];
+        break;
       }
     }
   }
@@ -27,10 +36,8 @@ export function parseByLocationRegexp(text: string, position: number, regexp: Re
 
 export function parseByLocationRegexps(text: string, position: number, regexps: RegExp[]) {
   for (let regexp of regexps) {
-    let result;
-    if (result = parseByLocationRegexp(text, position, regexp)) {
-      return result;
-    }  
+    let result = parseByLocationRegexp(text, position, regexp)
+    if (result) return result;
   }
 
   return null;

test/utils.test.ts

@@ -4,7 +4,7 @@ import * as assert from 'assert';
 suite('Utils Tests', () => {
   suite('parseByLocationRegexp', () => { 
     test('should match group only in given position', () => {
-      const regexp = /{{ (\w+) }}/g;
+      const regexp = /({{ )(\w+) }}/g;
       const input = '<span>{{ myVar1 }} {{ myVar2 }}</span>';
 
       assert.equal(parseByLocationRegexp(input, 8, regexp), null);