This package provides low-level APIs to support renderers like React Native. If you're looking for the standalone React DevTools UI, we suggest using react-devtools
instead of using this package directly.
This package provides two entrypoints: labeled "backend" and "standalone" (frontend). Both APIs are described below.
Backend APIs are embedded in development builds of renderers like React Native in order to connect to the React DevTools UI.
If you are building a non-browser-based React renderer, you can use the backend API like so:
if (process.env.NODE_ENV !== 'production') {
const { initialize, connectToDevTools } = require("react-devtools-core");
initialize(settings);
// Must be called before packages like react or react-native are imported
connectToDevTools({...config});
}
NOTE that this API (
connectToDevTools
) must be (1) run in the same context as React and (2) must be called before React packages are imported (e.g.react
,react-dom
,react-native
).
Argument | Description |
---|---|
settings |
Optional. If not specified, or received as null, then default settings are used. Can be plain object or a Promise that resolves with the plain settings object. If Promise rejects, the console will not be patched and some console features from React DevTools will not work. |
Spec | Default value |
---|---|
{ |
{ |
Prop | Default | Description |
---|---|---|
host |
"localhost" |
Socket connection to frontend should use this host. |
isAppActive |
(Optional) function that returns true/false, telling DevTools when it's ready to connect to React. | |
port |
8097 |
Socket connection to frontend should use this port. |
resolveRNStyle |
(Optional) function that accepts a key (number) and returns a style (object); used by React Native. | |
retryConnectionDelay |
200 |
Delay (ms) to wait between retrying a failed Websocket connection |
useHttps |
false |
Socket connection to frontend should use secure protocol (wss). |
websocket |
Custom WebSocket connection to frontend; overrides host and port settings. |
|
onSettingsUpdated |
A callback that will be called when the user updates the settings in the UI. You can use it for persisting user settings. |
Prop | Description |
---|---|
onSubscribe |
Function, which receives listener (function, with a single argument) as an argument. Called when backend subscribes to messages from the other end (frontend). |
onUnsubscribe |
Function, which receives listener (function) as an argument. Called when backend unsubscribes to messages from the other end (frontend). |
onMessage |
Function, which receives 2 arguments: event (string) and payload (any). Called when backend emits a message, which should be sent to the frontend. |
onSettingsUpdated |
A callback that will be called when the user updates the settings in the UI. You can use it for persisting user settings. |
Unlike connectToDevTools
, connectWithCustomMessagingProtocol
returns a callback, which can be used for unsubscribing the backend from the global DevTools hook.
Frontend APIs can be used to render the DevTools UI into a DOM node. One example of this is react-devtools
which wraps DevTools in an Electron app.
import DevtoolsUI from "react-devtools-core/standalone";
// See the full list of API methods in documentation below.
const { setContentDOMNode, startServer } = DevtoolsUI;
// Render DevTools UI into a DOM element.
setContentDOMNode(document.getElementById("container"));
// Start socket server used to communicate between backend and frontend.
startServer(
// Port defaults to 8097
1234,
// Host defaults to "localhost"
"example.devserver.com",
// Optional config for secure socket (WSS).
{
key: fs.readFileSync('test/fixtures/keys/agent2-key.pem'),
cert: fs.readFileSync('test/fixtures/keys/agent2-cert.pem')
}
);
The default
export is an object defining the methods described below.
These methods support chaining for convenience. For example:
const DevtoolsUI = require("react-devtools-core/standalone");
DevtoolsUI.setContentDOMNode(element).startServer();
This is an advanced config function that is typically not used.
Custom WebSocket
connection to use for communication between DevTools frontend and backend. Calling this method automatically initializes the DevTools UI (similar to calling startServer()
).
Automatically select the "Profiler" tab in the DevTools UI.
Set the DOM element DevTools UI should be rendered into on initialization.
Optional callback to be notified when DevTools WebSocket
closes (or errors).
Optional set of root directories for source files. These roots can be used to open an inspected component's source code using an IDE.
Optional callback to be notified of socket server events (e.g. initialized, errored, connected).
This callback receives two parameters:
function onStatus(
message: string,
status: 'server-connected' | 'devtools-connected' | 'error'
): void {
// ...
}
Start a socket server (used to communicate between backend and frontend) and renders the DevTools UI.
This method accepts the following parameters:
Name | Default | Description |
---|---|---|
port |
8097 |
Socket connection to backend should use this port. |
host |
"localhost" |
Socket connection to backend should use this host. |
httpsOptions |
Optional object defining key and cert strings. |
|
loggerOptions |
Optional object defining a surface string (to be included with DevTools logging events). |
Watch for changes made to the backend entry point and rebuild:
yarn start:backend
Watch for changes made to the standalone UI entry point and rebuild:
yarn start:standalone
Run the standalone UI using yarn start
in the react-devtools
.