Cope with backslash selectors (#426)

* cope with backslash: selectors

* function name

Author: peterbe

src/utils.js

@@ -27,9 +27,10 @@ function memoize(fn) {
  * @return {string}
  */
 const reduceCSSSelector = memoize((selector) => {
-  return selector.split(
-    /:(?=([^"'\\]*(\\.|["']([^"'\\]*\\.)*[^"'\\]*['"]))*[^"']*$)/g
-  )[0];
+  selector = selector.replace('\\:', '_ESCAPED_COLON_');
+  return selector
+    .split(/:(?=([^"'\\]*(\\.|["']([^"'\\]*\\.)*[^"'\\]*['"]))*[^"']*$)/g)[0]
+    .replace('_ESCAPED_COLON_', '\\:');
 });
 
 /**

tests/utils.test.js

@@ -20,6 +20,10 @@ test('Test reduceCSSSelector', async () => {
   expect(f("a[href^='javascript:']:after")).toEqual("a[href^='javascript:']");
 });
 
+test('Test backslash selectors', async () => {
+  expect(utils.reduceCSSSelector('foo\\:hover')).toEqual('foo\\:hover');
+});
+
 test('Test parentSelectors', async () => {
   const f = utils.getParentSelectors;
   // Simplest possible