JavaScript - indent non-block bodies of if, while, for (#6186)

Author: greg-at-moderne

rewrite-javascript/rewrite/src/javascript/format.ts

@@ -1145,7 +1145,26 @@ export class TabsAndIndentsVisitor<P> extends JavaScriptVisitor<P> {
 
     protected async preVisit(tree: J, p: P): Promise<J | undefined> {
         const ret = await super.preVisit(tree, p);
-        const indentShouldIncrease = tree.kind === J.Kind.Block || tree.kind === J.Kind.Case;
+        let indentShouldIncrease = tree.kind === J.Kind.Block || tree.kind === J.Kind.Case;
+
+        // Increase indent for control structures with non-block bodies
+        if (tree.kind === J.Kind.If) {
+            const ifStmt = tree as J.If;
+            if (ifStmt.thenPart.element.kind !== J.Kind.Block) {
+                indentShouldIncrease = true;
+            }
+        } else if (tree.kind === J.Kind.WhileLoop) {
+            const whileLoop = tree as J.WhileLoop;
+            if (whileLoop.body.element.kind !== J.Kind.Block) {
+                indentShouldIncrease = true;
+            }
+        } else if (tree.kind === J.Kind.ForLoop) {
+            const forLoop = tree as J.ForLoop;
+            if (forLoop.body.element.kind !== J.Kind.Block) {
+                indentShouldIncrease = true;
+            }
+        }
+
         if (indentShouldIncrease) {
             this.cursor.messages.set("indentToUse", this.currentIndent + this.singleIndent);
         }

rewrite-javascript/rewrite/test/javascript/format/tabs-and-indents-visitor.test.ts

@@ -284,4 +284,34 @@ describe('TabsAndIndentsVisitor', () => {
             // @formatter:on
         )
     })
+
+    test("collapsed if/while", () => {
+        const spec = new RecipeSpec()
+        spec.recipe = fromVisitor(new TabsAndIndentsVisitor(tabsAndIndents(draft => {})));
+        return spec.rewriteRun(
+            // @formatter:off
+            //language=typescript
+            typescript(
+               `
+                if (504 == 436)
+                console.log("That's practically true!");
+                if (407 == 501)
+                    console.log("Also true!");
+                while (!areWeThereYet())
+                 wait();
+                if (116 == 119) console.log("Close, but false. No changes");
+                `,
+                `
+                if (504 == 436)
+                    console.log("That's practically true!");
+                if (407 == 501)
+                    console.log("Also true!");
+                while (!areWeThereYet())
+                    wait();
+                if (116 == 119) console.log("Close, but false. No changes");
+                `,
+                )
+            // @formatter:on
+        )
+    })
 });