---
source: crates/rome_formatter_test/src/snapshot_builder.rs
info:
  test_file: js/bind-expressions/method_chain.js
---

# Input

```js
import {interval} from 'rxjs/observable/interval';
import {filter} from 'rxjs/operator/filter';
import {take} from 'rxjs/operator/take';
import {map} from 'rxjs/operator/map';
import {throttle} from 'rxjs/operator/throttle';
import {takeUntil} from 'rxjs/operator/takeUntil';

function test(observable) {
    return observable
        ::filter(data => data.someTest)
        ::throttle(() =>
            interval(10)
                ::take(1)
                ::takeUntil(observable::filter(data => someOtherTest))
        )
        ::map(someFunction);
}

```


# Prettier differences

```diff
--- Prettier
+++ Rome
@@ -6,12 +6,12 @@
 import { takeUntil } from "rxjs/operator/takeUntil";
 
 function test(observable) {
-  return observable
-    ::filter((data) => data.someTest)
-    ::throttle(() =>
-      interval(10)
-        ::take(1)
-        ::takeUntil(observable::filter((data) => someOtherTest)),
-    )
-    ::map(someFunction);
+  return observable;
+  ::filter(data => data.someTest)
+        ::throttle(() =>
+            interval(10)
+                ::take(1)
+                ::takeUntil(observable::filter(data => someOtherTest))
+        )
+        ::map(someFunction)
 }
```

# Output

```js
import { interval } from "rxjs/observable/interval";
import { filter } from "rxjs/operator/filter";
import { take } from "rxjs/operator/take";
import { map } from "rxjs/operator/map";
import { throttle } from "rxjs/operator/throttle";
import { takeUntil } from "rxjs/operator/takeUntil";

function test(observable) {
  return observable;
  ::filter(data => data.someTest)
        ::throttle(() =>
            interval(10)
                ::take(1)
                ::takeUntil(observable::filter(data => someOtherTest))
        )
        ::map(someFunction)
}
```

# Errors
```
method_chain.js:10:9 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  × expected a statement but instead found '::filter(data => data.someTest)
            ::throttle(() =>
                interval(10)
                    ::take(1)
                    ::takeUntil(observable::filter(data => someOtherTest))
            )
            ::map(someFunction)'
  
     8 │ function test(observable) {
     9 │     return observable
  > 10 │         ::filter(data => data.someTest)
       │         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  > 11 │         ::throttle(() =>
        ...
  > 15 │         )
  > 16 │         ::map(someFunction);
       │         ^^^^^^^^^^^^^^^^^^^
    17 │ }
    18 │ 
  
  i Expected a statement here
  
     8 │ function test(observable) {
     9 │     return observable
  > 10 │         ::filter(data => data.someTest)
       │         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  > 11 │         ::throttle(() =>
        ...
  > 15 │         )
  > 16 │         ::map(someFunction);
       │         ^^^^^^^^^^^^^^^^^^^
    17 │ }
    18 │ 
  

```