---
source: crates/rome_formatter_test/src/snapshot_builder.rs
info:
  test_file: js/rest/trailing-commas.js
---

# Input

```js
declare class C {
  f(
    superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
    ...args
  ): void,
}

function f(
  superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
  ...args
) {}

declare class C { f(...superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong): void; }

[superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,,];

[veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLong, ...a] = [];
var {veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLong, ...a} = {};


```


# Prettier differences

```diff
--- Prettier
+++ Rome
@@ -2,7 +2,7 @@
   f(
     superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
     ...args
-  ): void;
+  ): void,
 }
 
 function f(
@@ -10,11 +10,7 @@
   ...args
 ) {}
 
-declare class C {
-  f(
-    ...superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong
-  ): void;
-}
+declare class C { f(...superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong): void; }
 
 [
   superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
```

# Output

```js
declare class C {
  f(
    superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
    ...args
  ): void,
}

function f(
  superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
  ...args
) {}

declare class C { f(...superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong): void; }

[
  superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
  ,
];

[
  veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLong,
  ...a
] = [];
var {
  veryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLong,
  ...a
} = {};
```

# Errors
```
trailing-commas.js:1:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × The 'declare' modifier can only be used in TypeScript files.
  
  > 1 │ declare class C {
      │ ^^^^^^^
    2 │   f(
    3 │     superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
  
trailing-commas.js:13:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × The 'declare' modifier can only be used in TypeScript files.
  
    11 │ ) {}
    12 │ 
  > 13 │ declare class C { f(...superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong): void; }
       │ ^^^^^^^
    14 │ 
    15 │ [superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,,];
  

```

# Lines exceeding max width of 80 characters
```
   13: declare class C { f(...superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong): void; }
   16:   superSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperSuperLong,
```