plus and minus

Author: jasonlyu123

packages/svelte2tsx/src/utils/htmlxparser.ts

@@ -128,7 +128,9 @@ const possibleOperatorOrPropertyAccess = [
     '&',
     '^',
     '|',
-    ','
+    ',',
+    '+',
+    '-'
 ];
 
 function blankPossiblyErrorOperatorOrPropertyAccess(htmlx: string) {
@@ -141,8 +143,18 @@ function blankPossiblyErrorOperatorOrPropertyAccess(htmlx: string) {
         while (backwardIndex > lastIndex) {
             const char = htmlx.charAt(backwardIndex);
             if (possibleOperatorOrPropertyAccess.includes(char)) {
-                htmlx =
-                    htmlx.substring(0, backwardIndex) + ' ' + htmlx.substring(backwardIndex + 1);
+                const previous = backwardIndex - 1;
+                const isPlusOrMinus = char === '+' || char === '-';
+                const isIncrementOrDecrement = isPlusOrMinus && htmlx.charAt(previous) === char;
+                const start = isIncrementOrDecrement ? previous : backwardIndex;
+                const replacement = isIncrementOrDecrement ? '  ' : ' ';
+
+                if (!isPlusOrMinus) {
+                    htmlx =
+                        htmlx.substring(0, start) +
+                        replacement +
+                        htmlx.substring(backwardIndex + 1);
+                }
             } else if (!/\s/.test(char)) {
                 break;
             }

packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/expected.jsx

@@ -1,3 +1,4 @@
 <>{abc.   }
 {abc?. }
-{abc ?}</>
+{abc ?}
+{a+}</>

packages/svelte2tsx/test/htmlx2jsx/samples/editing-mustache/input.svelte

@@ -1,3 +1,4 @@
 {abc.   }
 {abc?. }
 {abc ?}
+{a+}