# Runtime validations

{% embed url="<https://youtu.be/_67r4wq23BA?t=599>" %}

You can provide your own runtime validations methods that will return a boolean for if the command should actually be ran or not.

{% tabs %}
{% tab title="JavaScript" %}
{% code title="command-starts-with-a.js" %}

```javascript
module.exports = (command, usage, prefix) => {
  return command.commandName.startsWith("a");
};
```

{% endcode %}
{% endtab %}

{% tab title="TypeScript" %}
{% code title="command-starts-with-a.js" %}

```typescript
import { CommandUsage, Command } from "wokcommands";

export default (command: Command, usage: CommandUsage, prefix: string) => {
  return command.commandName.startsWith("a");
};
```

{% endcode %}
{% endtab %}
{% endtabs %}