---
source: crates/biome_formatter_test/src/snapshot_builder.rs
info: js/babel-plugins/pipeline-operator-hack.js
---

# Input

```js
// https://babeljs.io/docs/en/babel-plugin-proposal-pipeline-operator
// https://github.com/js-choi/proposal-hack-pipes

return list
 |> take(prefix.length, %)
 |> equals(%, prefix);

// (The % token isn't final; it might instead be @ or ? or #.)

```


# Prettier differences

```diff
--- Prettier
+++ Biome
@@ -1,6 +1,8 @@
 // https://babeljs.io/docs/en/babel-plugin-proposal-pipeline-operator
 // https://github.com/js-choi/proposal-hack-pipes
 
-return list |> take(prefix.length, %) |> equals(%, prefix);
+return list
+ |> take(prefix.length, %)
+ |> equals(%, prefix);
 
 // (The % token isn't final; it might instead be @ or ? or #.)
```

# Output

```js
// https://babeljs.io/docs/en/babel-plugin-proposal-pipeline-operator
// https://github.com/js-choi/proposal-hack-pipes

return list
 |> take(prefix.length, %)
 |> equals(%, prefix);

// (The % token isn't final; it might instead be @ or ? or #.)
```

# Errors
```
pipeline-operator-hack.js:5:3 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Expected an expression for the left hand side of the `>` operator.
  
    4 │ return list
  > 5 │  |> take(prefix.length, %)
      │   ^
    6 │  |> equals(%, prefix);
    7 │ 
  
  i This operator requires a left hand side value
  
pipeline-operator-hack.js:5:25 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Expected an expression for the left hand side of the `%` operator.
  
    4 │ return list
  > 5 │  |> take(prefix.length, %)
      │                         ^
    6 │  |> equals(%, prefix);
    7 │ 
  
  i This operator requires a left hand side value
  
pipeline-operator-hack.js:5:26 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Expected an expression but instead found ')'.
  
    4 │ return list
  > 5 │  |> take(prefix.length, %)
      │                          ^
    6 │  |> equals(%, prefix);
    7 │ 
  
  i Expected an expression here.
  
    4 │ return list
  > 5 │  |> take(prefix.length, %)
      │                          ^
    6 │  |> equals(%, prefix);
    7 │ 
  
pipeline-operator-hack.js:6:3 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Expected an expression for the left hand side of the `>` operator.
  
    4 │ return list
    5 │  |> take(prefix.length, %)
  > 6 │  |> equals(%, prefix);
      │   ^
    7 │ 
    8 │ // (The % token isn't final; it might instead be @ or ? or #.)
  
  i This operator requires a left hand side value
  
pipeline-operator-hack.js:6:12 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Expected an expression for the left hand side of the `%` operator.
  
    4 │ return list
    5 │  |> take(prefix.length, %)
  > 6 │  |> equals(%, prefix);
      │            ^
    7 │ 
    8 │ // (The % token isn't final; it might instead be @ or ? or #.)
  
  i This operator requires a left hand side value
  
pipeline-operator-hack.js:6:13 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Expected an expression but instead found ','.
  
    4 │ return list
    5 │  |> take(prefix.length, %)
  > 6 │  |> equals(%, prefix);
      │             ^
    7 │ 
    8 │ // (The % token isn't final; it might instead be @ or ? or #.)
  
  i Expected an expression here.
  
    4 │ return list
    5 │  |> take(prefix.length, %)
  > 6 │  |> equals(%, prefix);
      │             ^
    7 │ 
    8 │ // (The % token isn't final; it might instead be @ or ? or #.)
  
pipeline-operator-hack.js:4:1 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × Illegal return statement outside of a function
  
    2 │ // https://github.com/js-choi/proposal-hack-pipes
    3 │ 
  > 4 │ return list
      │ ^^^^^^^^^^^
  > 5 │  |> take(prefix.length, %)
  > 6 │  |> equals(%, prefix);
      │  ^^^^^^^^^^^^^^^^^^^^^
    7 │ 
    8 │ // (The % token isn't final; it might instead be @ or ? or #.)
  

```