---
source: crates/biome_formatter_test/src/snapshot_builder.rs
info: js/babel-plugins/do-expressions.js
---

# Input

```js
// https://babeljs.io/docs/en/babel-plugin-proposal-do-expressions

let a = do {
  if(x > 10) {
    'big';
  } else {
    'small';
  }
};
// is equivalent to:
let a = x > 10 ? 'big' : 'small';

```


# Prettier differences

```diff
--- Prettier
+++ Biome
@@ -1,10 +1,11 @@
 // https://babeljs.io/docs/en/babel-plugin-proposal-do-expressions
 
-let a = do {
-  if (x > 10) {
-    ("big");
+let a =
+do {
+  if(x > 10) {
+    'big';
   } else {
-    ("small");
+    'small';
   }
 };
 // is equivalent to:
```

# Output

```js
// https://babeljs.io/docs/en/babel-plugin-proposal-do-expressions

let a =
do {
  if(x > 10) {
    'big';
  } else {
    'small';
  }
};
// is equivalent to:
let a = x > 10 ? "big" : "small";
```

# Errors
```
do-expressions.js:3:9 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Expected an expression, or an assignment but instead found 'do'.
  
    1 │ // https://babeljs.io/docs/en/babel-plugin-proposal-do-expressions
    2 │ 
  > 3 │ let a = do {
      │         ^^
    4 │   if(x > 10) {
    5 │     'big';
  
  i Expected an expression, or an assignment here.
  
    1 │ // https://babeljs.io/docs/en/babel-plugin-proposal-do-expressions
    2 │ 
  > 3 │ let a = do {
      │         ^^
    4 │   if(x > 10) {
    5 │     'big';
  
do-expressions.js:9:2 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × expected `while` but instead found `;`
  
     7 │     'small';
     8 │   }
   > 9 │ };
       │  ^
    10 │ // is equivalent to:
    11 │ let a = x > 10 ? 'big' : 'small';
  
  i Remove ;
  

```