Consistently use tabs in ternaries when useTabs is true (#15662)

Co-authored-by: fisker Cheung <[email protected]>
Co-authored-by: SUZUKI Sosuke <[email protected]>

Author: 3 people

changelog_unreleased/javascript/15662.md

@@ -0,0 +1,31 @@
+#### Consistently use tabs in ternaries when `useTabs` is `true` (#15662 by @auvred)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+aaaaaaaaaaaaaaa
+	? bbbbbbbbbbbbbbbbbb
+	: ccccccccccccccc
+	  ? ddddddddddddddd
+	  : eeeeeeeeeeeeeee
+	    ? fffffffffffffff
+	    : gggggggggggggggg;
+
+// Prettier stable
+aaaaaaaaaaaaaaa
+	? bbbbbbbbbbbbbbbbbb
+	: ccccccccccccccc
+	  ? ddddddddddddddd
+	  : eeeeeeeeeeeeeee
+	    ? fffffffffffffff
+	    : gggggggggggggggg;
+
+// Prettier main
+aaaaaaaaaaaaaaa
+	? bbbbbbbbbbbbbbbbbb
+	: ccccccccccccccc
+		? ddddddddddddddd
+		: eeeeeeeeeeeeeee
+			? fffffffffffffff
+			: gggggggggggggggg;
+```

src/language-js/print/ternary-old.js

@@ -274,16 +274,42 @@ function printTernaryOld(path, options, print) {
         : wrap(print(alternateNodePropertyName)),
     );
   } else {
+    /*
+    This does not mean to indent, but make the doc aligned with the first character after `? ` or `: `,
+    so we use `2` instead of `options.tabWidth` here.
+    
+    ```js
+    test
+     ? {
+         consequent
+       }
+     : alternate
+    ```
+
+    instead of
+    
+    ```js
+    test
+     ? {
+       consequent
+     }
+     : alternate
+    ```
+    */
+    const printBranch = (nodePropertyName) =>
+      options.useTabs
+        ? indent(print(nodePropertyName))
+        : align(2, print(nodePropertyName));
     // normal mode
     const part = [
       line,
       "? ",
       consequentNode.type === node.type ? ifBreak("", "(") : "",
-      align(2, print(consequentNodePropertyName)),
+      printBranch(consequentNodePropertyName),
       consequentNode.type === node.type ? ifBreak("", ")") : "",
       line,
       ": ",
-      align(2, print(alternateNodePropertyName)),
+      printBranch(alternateNodePropertyName),
     ];
     parts.push(
       parent.type !== node.type ||