---
url: /docs/guide/usage/linter/rules/promise/catch-or-return.md
---

### What it does

Ensure that each time a `then()` is applied to a promise, a `catch()`
must be applied as well. Exceptions are made for promises returned from
a function.

### Why is this bad?

Not catching errors in a promise can cause hard to debug problems or
missing handling of error conditions. In the worst case, unhandled
promise rejections can cause your application to crash.

### Examples

Examples of **incorrect** code for this rule:

```javascript
myPromise.then(doSomething);
myPromise.then(doSomething, catchErrors); // catch() may be a little better
```

Examples of **correct** code for this rule:

```javascript
myPromise.then(doSomething).catch(errors);
function doSomethingElse() {
  return myPromise.then(doSomething);
}
const arrowFunc = () => myPromise.then(doSomething);
```

## Configuration

This rule accepts a configuration object with the following properties:

### allowFinally

type: `boolean`

default: `false`

Whether to allow `finally()` as a termination method.

### allowThen

type: `boolean`

default: `false`

Whether to allow `then()` with two arguments as a termination method.

### allowThenStrict

type: `boolean`

default: `false`

Whether to allow `then(null, handler)` as a termination method.

### terminationMethod

type: `array | string`

#### terminationMethod\[n]

type: `string`

## How to use

## Version

This rule was added in v0.9.2.

## References