fix: restore edited x value on escape

samples/dev/index.js

@@ -21,6 +21,7 @@ let stackCursor = null;
 let isMovingStackItem = false;
 let stackSnapshotBeforeMove = null;
 let stackViewOffset = 0;
+let editRestoreValue = null;
 
 function labelFor(command) {
   return ({ add: '+', sub: '−', mul: '×', div: '÷', pow: 'y^x', recip: '1/x', sqr: 'x²' }[command] || command);
@@ -105,9 +106,11 @@ function reactivateEditOnX() {
     calc.remove(0);
     calc.inputValue = calc.formatNumber(value);
     calc.isEditing = true;
+    editRestoreValue = value;
   } else {
     calc.inputValue = '';
     calc.isEditing = true;
+    editRestoreValue = null;
   }
   syncInputFromState();
 }
@@ -217,6 +220,7 @@ function pushEditingValueIfNeeded() {
   }
   calc.inputValue = '';
   calc.isEditing = false;
+  editRestoreValue = null;
   syncInputFromState();
 }
 
@@ -351,6 +355,7 @@ function editXWithKey(key) {
     pushEditingValueIfNeeded();
     calc.isEditing = true;
     calc.inputValue = '';
+    editRestoreValue = null;
   }
   if (key === 'Backspace') {
     calc.inputValue = calc.inputValue.slice(0, -1);
@@ -359,6 +364,7 @@ function editXWithKey(key) {
   }
   if (calc.inputValue === '') {
     calc.isEditing = false;
+    editRestoreValue = null;
   }
   syncInputFromState();
 }
@@ -377,6 +383,10 @@ function handleKeydown(event) {
     if (action.type === 'escapeKey') {
       if (calc.isEditing) {
         event.preventDefault();
+        if (editRestoreValue !== null) {
+          calc.push(editRestoreValue);
+          editRestoreValue = null;
+        }
         calc.inputValue = '';
         calc.isEditing = false;
         syncInputFromState();