Fix random matches are missed + add test

Alternative implementation to #47

src/lib/TextExtraction.js

@@ -52,7 +52,7 @@ class TextExtraction {
           );
 
           textLeft = textLeft.substr(matches.index + matches[0].length);
-          indexOfMatchedString += matches[0].length;
+          indexOfMatchedString += matches[0].length - 1;
           // Global RegExps are stateful, this makes it operate on the "remainder" of the string
           pattern.pattern.lastIndex = indexOfMatchedString;
         }

test/TextExtraction.test.js

@@ -28,6 +28,34 @@ describe('TextExtraction', () => {
       expect(textExtraction.parse()).toEqual([{ children: 'abcdef' }]);
     });
 
+    it('still works even if the RegExp has a previously-used pattern', () => {
+      const r = /c/g;
+      r.lastIndex = 2;
+      const textExtraction = new TextExtraction('cc something c something', [
+        { pattern: r, renderText: () => 'Found!' },
+      ]);
+
+      expect(textExtraction.parse()).toMatchInlineSnapshot(`
+        Array [
+          Object {
+            "children": "Found!",
+          },
+          Object {
+            "children": "Found!",
+          },
+          Object {
+            "children": " something ",
+          },
+          Object {
+            "children": "Found!",
+          },
+          Object {
+            "children": " something",
+          },
+        ]
+      `);
+    });
+
     it('returns an array with text parts if there is matches', () => {
       const textExtraction = new TextExtraction(
         'hello my website is http://foo.bar, bar is good.',