---
url: /docs/guide/usage/linter/rules/vue/no-reserved-keys.md
---

### What it does

Disallow overwriting reserved Vue instance keys (e.g. `$data`, `$emit`)
or using `_`-prefixed keys inside `data` / `asyncData`.

### Why is this bad?

Vue exposes a number of instance properties (`$emit`, `$data`, `$props`,
etc.). Defining a prop, computed, data, method or setup return key with
the same name overwrites the underlying Vue API and silently breaks the
component (e.g. `methods: { $emit() {} }` clobbers event emission).
Vue also reserves `_`-prefixed names inside its reactivity system, so
`data() { return { _foo: 1 } }` may collide with internal state.

### Examples

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

```vue
<script>
export default {
  props: ["$data"],
  methods: {
    $emit() {},
  },
};
</script>
```

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

```vue
<script>
export default {
  props: ["fooData"],
  methods: {
    send() {},
  },
};
</script>
```

## Configuration

### groups

type: `string[]`

default: `[]`

Extra component option groups to inspect, on top of the built-in
`props` / `computed` / `data` / `asyncData` / `methods` / `setup`.

### reserved

type: `string[]`

default: `[]`

Extra reserved key names to disallow, on top of the built-in list.

## How to use

## Version

This rule was added in v1.69.0.

## References