react-reconciler

import React from 'react'; import Reconciler from 'react-reconciler'; // Minimal HostConfig for a 'console' renderer const hostConfig = { now: Date.now, supportsMutation: true, // Or supportsPersistence: true for immutable trees getRootHostContext: () => ({}), getChildHostContext: (parentHostContext, type) => parentHostContext, getPublicInstance: (instance) => instance, prepareForCommit: () => null, resetAfterCommit: () => {}, createInstance: (type, props, rootContainerInstance, hostContext, internalInstanceHandle) => { // In a real renderer, this would create a DOM node, canvas object, etc. const instance = { type, props, children: [] }; console.log(`CREATE: <${type}>`, props); return instance; }, createTextInstance: (text, rootContainerInstance, hostContext, internalInstanceHandle) => { console.log(`CREATE TEXT: "${text}"`); return text; }, appendInitialChild: (parentInstance, child) => { parentInstance.children.push(child); console.log(`APPEND INITIAL CHILD:`, { parent: parentInstance.type, child }); }, appendChild: (parentInstance, child) => { parentInstance.children.push(child); console.log(`APPEND CHILD:`, { parent: parentInstance.type, child }); }, insertBefore: (parentInstance, child, beforeChild) => { const index = parentInstance.children.indexOf(beforeChild); if (index > -1) { parentInstance.children.splice(index, 0, child); } console.log(`INSERT BEFORE:`, { parent: parentInstance.type, child, before: beforeChild }); }, removeChild: (parentInstance, child) => { parentInstance.children = parentInstance.children.filter(c => c !== child); console.log(`REMOVE CHILD:`, { parent: parentInstance.type, child }); }, prepareUpdate: (instance, type, oldProps, newProps, rootContainerInstance, hostContext) => { // Compare oldProps and newProps to determine what needs to change. const payload = {}; for (const key in newProps) { if (newProps[key] !== oldProps[key]) { payload[key] = newProps[key]; } } return Object.keys(payload).length > 0 ? payload : null; }, commitUpdate: (instance, updatePayload, type, oldProps, newProps, internalHandle) => { Object.assign(instance.props, updatePayload); console.log(`UPDATE: <${type}>`, updatePayload); }, commitTextUpdate: (textInstance, oldText, newText) => { console.log(`TEXT UPDATE: "${oldText}" -> "${newText}"`); Object.assign(textInstance, newText); // Assuming textInstance is mutable string or wrapper }, shouldSetTextContent: (type, props) => typeof props.children === 'string' || typeof props.children === 'number', // Add other required methods like scheduleTimeout, cancelTimeout, noTimeout, etc. scheduleTimeout: setTimeout, cancelTimeout: clearTimeout, noTimeout: -1, isPrimaryRenderer: true, getCurrentEventPriority: () => 3, // DefaultEventPriority (requires import from 'react-reconciler/constants') // A minimal set of methods is still quite large. Many can be no-ops initially. }; const MyRenderer = Reconciler(hostConfig); const rootContainer = {}; // Represents the 'host' root, e.g., a canvas element, a terminal object const root = MyRenderer.createContainer(rootContainer, false, false); // No hydrate, no hydrationCallbacks export function render(element, container) { // `container` here would be the root object in your host environment // like `document.getElementById('root')` for ReactDOM. // For this console example, we'll just use the `rootContainer` created above. MyRenderer.updateContainer(element, root, null, () => { console.log('RENDER COMPLETE!', rootContainer); // For a console renderer, you'd print the final tree here. // In a real app, this would trigger a flush of pending updates to the actual UI. }); } // Example usage function App() { const [count, setCount] = React.useState(0); React.useEffect(() => { const interval = setInterval(() => setCount(c => c + 1), 1000); return () => clearInterval(interval); }, []); return ( <box color="blue"> <text>{`Count: ${count}`}</text> <button onClick={() => setCount(0)}>Reset</button> </box> ); } render(<App />, rootContainer);