Fix a bug with eslint parsing which mistakenly cleared markers

ale_linters/javascript/eslint.vim

@@ -9,24 +9,32 @@ function! ale_linters#javascript#eslint#Handle(lines)
     "
     " <text>:47:14: Missing trailing comma. [Warning/comma-dangle]
     " <text>:56:41: Missing semicolon. [Error/semi]
-    let pattern = '^<text>:\(\d\+\):\(\d\+\): \(.\+\) \[\(.\+\)/\(.\+\)\]'
+    let pattern = '^<text>:\(\d\+\):\(\d\+\): \(.\+\) \[\(.\+\)\]'
     let output = []
 
     for line in a:lines
-        let match = matchlist(line, pattern)
+        let l:match = matchlist(line, pattern)
 
-        if len(match) == 0
+        if len(l:match) == 0
             break
         endif
 
+        let text = l:match[3]
+        let marker_parts = l:match[4]
+        let type = marker_parts[0]
+
+        if len(marker_parts) == 2
+            let text = text . ' (' . marker_parts[1] . ')'
+        endif
+
         " vcol is Needed to indicate that the column is a character.
         call add(output, {
         \   'bufnr': bufnr('%'),
-        \   'lnum': match[1] + 0,
+        \   'lnum': l:match[1] + 0,
         \   'vcol': 0,
-        \   'col': match[2] + 0,
-        \   'text': match[3] . '(' . match[5] . ')',
-        \   'type': match[4] ==# 'Warning' ? 'W' : 'E',
+        \   'col': l:match[2] + 0,
+        \   'text': text,
+        \   'type': type ==# 'Warning' ? 'W' : 'E',
         \   'nr': -1,
         \})
     endfor