# Objective
Add a method to mutate components with BRP.
Currently the only way to modify a component on an entity with BRP is to
insert a new one with the new values. This isn't ideal for several
reasons, one reason being that the client has to know what all the
fields are of the component and stay in sync with the server.
## Solution
Add a new BRP method called `bevy/mutate_component` to mutate a single
field in a component on an entity.
## Testing
Tested on a simple scene on all `Transform`, `Name`, and a custom
component.
---
## Showcase
Example JSON-RPC request to change the `Name` of an entity to "New
name!"
```json
{
"jsonrpc": "2.0",
"id": 0,
"method": "bevy/mutate_component",
"params": {
"entity": 4294967308,
"component": "bevy_ecs::name::Name",
"path": ".name",
"value": "New name!"
}
}
```
Or setting the X translation to 10.0 on a Transform:
```json
{
"jsonrpc": "2.0",
"id": 0,
"method": "bevy/mutate_component",
"params": {
"entity": 4294967308,
"component": "bevy_transform::components::transform::Transform",
"path": ".translation.x",
"value": 10.0
}
}
```
Clip of my Emacs BRP package using this method:
https://github.com/user-attachments/assets/a786b245-5c20-4189-859f-2261c5086a68
---------
Co-authored-by: François Mockers <mockersf@gmail.com>
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