fix: fix scraping JSON with escaped backslashes towards end of strings (

#862)

* fix escaped backslashes towards end of string & add test

* Update lib/utils.js

Co-authored-by: fent <fentbox@gmail.com>

* linting

Co-authored-by: fent <fentbox@gmail.com>

lib/utils.js

@@ -72,16 +72,24 @@ exports.cutAfterJSON = mixedJson => {
   // States if the loop is currently in a string
   let isString = false;
 
+  // States if the current character is treated as escaped or not
+  let isEscaped = false;
+
   // Current open brackets to be closed
   let counter = 0;
 
   let i;
   for (i = 0; i < mixedJson.length; i++) {
     // Toggle the isString boolean when leaving/entering string
-    if (mixedJson[i] === '"' && mixedJson[i - 1] !== '\\') {
+    if (mixedJson[i] === '"' && !isEscaped) {
       isString = !isString;
       continue;
     }
+
+    // Toggle the isEscaped boolean for every backslash
+    // Reset for every regular character
+    isEscaped = mixedJson[i] === '\\' && !isEscaped;
+
     if (isString) continue;
 
     if (mixedJson[i] === open) {

test/utils-test.js

@@ -63,6 +63,12 @@ describe('utils.cutAfterJSON()', () => {
       '{"a": "\\\\фыва", "b": 1, "c": {"test": 1}}',
     );
   });
+  it('Works with \\\\ towards the end of a string', () => {
+    assert.strictEqual(
+      utils.cutAfterJSON('{"text": "\\\\"};'),
+      '{"text": "\\\\"}',
+    );
+  });
   it('Works with [ as start', () => {
     assert.strictEqual(
       utils.cutAfterJSON('[{"a": 1}, {"b": 2}]abcd'),