diff --git a/__tests__/filters-downloader.test.js b/__tests__/filters-downloader.test.js
index 53f9feb..4bb2a03 100644
--- a/__tests__/filters-downloader.test.js
+++ b/__tests__/filters-downloader.test.js
@@ -1,4 +1,4 @@
-/* global QUnit */
+/* global QUnit, assert */
 /* eslint-disable global-require */
 
 const FilterCompilerConditionsConstants = {
@@ -590,7 +590,7 @@ QUnit.test('Test filter downloader - invalid "if" conditions', async (assert) =>
         'if_chromium_rule',
         '!#elseif adguard_ext_firefox',
         'invalid_else',
-        '!#endif'
+        '!#endif',
     ];
     assert.throws(() => {
         FilterDownloader.resolveConditions(rules, FilterCompilerConditionsConstants);
@@ -795,7 +795,7 @@ QUnit.test('Test filter downloader - simple "if" conditions with "else" branch',
         'adguard_included_rule',
         '!#else',
         'non_adguard_included_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -811,7 +811,7 @@ QUnit.test('Test filter downloader - simple "if" conditions with "else" branch',
         '!#else',
         'adguard_included_rule_1',
         'adguard_included_rule_2',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -827,7 +827,7 @@ QUnit.test('Test filter downloader - simple "if" conditions with "else" branch',
         'adguard_included_rule',
         '!#else',
         'non_adguard_included_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -847,7 +847,7 @@ QUnit.test('Test filter downloader - simple "if" conditions with "else" branch',
         'adguard_ext_chromium_included_rule',
         '!#else',
         'non_adguard_included_rule_2',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -868,7 +868,7 @@ QUnit.test('Test filter downloader - simple "if" conditions with "else" branch',
         'non_adguard_included_rule_2',
         '!#else',
         'adguard_ext_chromium_included_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -892,7 +892,7 @@ QUnit.test('Test filter downloader - logical "if" conditions with "else" branch'
         'adguard_included_rule',
         '!#else',
         'non_adguard_included_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -997,7 +997,7 @@ QUnit.test('Test filter downloader - logical "if" conditions with "else" branch'
         'if_included_rule',
         '!#else',
         'else_included_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -1012,7 +1012,7 @@ QUnit.test('Test filter downloader - logical "if" conditions with "else" branch'
         'if_included_rule',
         '!#else',
         'else_included_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'always_included_rule',
@@ -1040,7 +1040,7 @@ QUnit.test('Test filter downloader - nested if conditions with else branch', asy
         '!#endif',
         '!#else',
         'else_first_level_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'zero_level_rule',
@@ -1066,7 +1066,7 @@ QUnit.test('Test filter downloader - nested if conditions with else branch', asy
         '!#endif',
         '!#else',
         'else_first_level_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'zero_level_rule',
@@ -1093,7 +1093,7 @@ QUnit.test('Test filter downloader - nested if conditions with else branch', asy
         '!#endif',
         '!#else',
         'else_first_level_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'zero_level_rule',
@@ -1115,7 +1115,7 @@ QUnit.test('Test filter downloader - nested if conditions with else branch', asy
         '!#endif',
         '!#else',
         'else_first_level_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'zero_level_rule',
@@ -1136,7 +1136,7 @@ QUnit.test('Test filter downloader - nested if conditions with else branch', asy
         '!#endif',
         '!#else',
         'else_first_level_rule',
-        '!#endif'
+        '!#endif',
     ];
     expected = [
         'zero_level_rule',
diff --git a/src/filters-downloader-creator.js b/src/filters-downloader-creator.js
index 0294ea9..42af924 100644
--- a/src/filters-downloader-creator.js
+++ b/src/filters-downloader-creator.js
@@ -31,9 +31,9 @@
  * https://github.com/AdguardTeam/AdguardBrowserExtension/issues/917
  */
 const FiltersDownloaderCreator = (FileDownloadWrapper) => {
-    const CONDITION_IF_DIRECTIVE_START = "!#if";
-    const CONDITION_ELSE_DIRECTIVE_START = "!#else";
-    const CONDITION_DIRECTIVE_END = "!#endif";
+    const CONDITION_IF_DIRECTIVE_START = '!#if';
+    const CONDITION_ELSE_DIRECTIVE_START = '!#else';
+    const CONDITION_DIRECTIVE_END = '!#endif';
 
     const CONDITION_OPERATOR_NOT = '!';
     const CONDITION_OPERATOR_AND = '&&';
@@ -248,7 +248,7 @@ const FiltersDownloaderCreator = (FileDownloadWrapper) => {
 
         let result = [];
 
-        for (let i = 0; i < rules.length; i++) {
+        for (let i = 0; i < rules.length; i += 1) {
             const rule = rules[i];
 
             if (rule.indexOf(CONDITION_IF_DIRECTIVE_START) === 0) {