Merge pull request #435 from gkottr/patch-1

Fix #434

Author: samgozman

docs/assets/js/converter.js

@@ -1,15 +1,34 @@
-document.getElementById('jstoyopta').addEventListener('keyup', function(){converter(true);}, false);
-document.getElementById('yopta').addEventListener('keyup', function(){converter(false);}, false);
+const jstoyopta = document.getElementById('jstoyopta');
+const yopta = document.getElementById('yopta');
 
+jstoyopta.addEventListener('keyup', function(){converter(true);}, false);
+yopta.addEventListener('keyup', function(){converter(false);}, false);
+
+jstoyopta.addEventListener('keydown', onKeyDown);
+yopta.addEventListener('keydown', onKeyDown);
+
+
+function onKeyDown(event) {
+    if (event.key !== 'Tab') return;
+
+    event.preventDefault();
+    
+    const textarea = event.target;
+    
+    const start = textarea.selectionStart;
+    const end = textarea.selectionEnd;
+
+    textarea.value = textarea.value.substring(0, start) + '    ' + textarea.value.substring(end);
+
+    textarea.selectionStart = textarea.selectionEnd = start + 4;
+}
 
 function converter(lang) {
   if(lang) {
     //переводим в йопту
-    const jstoyopta = document.getElementById('jstoyopta').value;
-    document.getElementById('yopta').value = window.yopta(jstoyopta, 'js');
+    yopta.value = window.yopta(jstoyopta.value, 'js');
   } else {
     //переводим из йопты
-    const ystojs = document.getElementById('yopta').value;
-    document.getElementById('jstoyopta').value = window.yopta(ystojs, 'ys');
+    jstoyopta.value = window.yopta(yopta.value, 'ys');
   }
 }