Caldera – Phoenix LiveView for Node and React

栏目: IT技术 · 发布时间: 4年前

内容简介:Caldera is a server-side execution environment for React. Think of it as the Node.js analog to Phoenix LiveView —This allows developers to rapidly build interactive and multiplayer applications without developing boilerplate around RPC layers (REST/GraphQL

:volcano:

Caldera is a server-side execution environment for React. Think of it as the Node.js analog to Phoenix LiveView — all of the application logic (including rendering) runs on the server, and DOM updates are sent to the client in real-time.

This allows developers to rapidly build interactive and multiplayer applications without developing boilerplate around RPC layers (REST/GraphQL/gRPC) and messaging primitives (WebSockets/subscriptions/etc).

Because it's built on top of the React reconciler, it's compatible with (currently, a reasonably useful subset of) the existing React API. Seewhat's currently includedandfor updates.

Installation

Run npm install caldera to install Caldera.

Examples

A simple example (chat room) to get started:

import React, { useState } from "react";
import { renderCalderaApp, makeSharedResource, useSharedState } from "caldera";
import fs from "fs";

const DATA_PATH = "messages.json";
const messagesResource = makeSharedResource(
  // Load initial messages
  fs.existsSync(DATA_PATH)
    ? JSON.parse(fs.readFileSync(DATA_PATH, "utf-8"))
    : []
);

const usePersistedMessages = () => {
  // Basic shared state, synced with all clients
  const [messages, setMessages] = useSharedState(messagesResource);
  return [
    messages,
    // Persist to disk (in prod, use a database)
    (newMessages) => {
      setMessages(newMessages);
      fs.writeFileSync(DATA_PATH, JSON.stringify(newMessages));
    },
  ];
};

const App = () => {
  const [messages, setMessages] = usePersistedMessages();
  // local state, persisted across client reconnects
  const [draftMsg, setDraftMsg] = useState("");

  return (
    <>
      <h1>Chat Room!</h1>
      {messages.map((message, i) => (
        <div key={i}>{message}</div>
      ))}
      <form
        onSubmit={(e) => {
          e.preventDefault();
          setMessages([...messages, draftMsg]);
          setDraftMsg("");
        }}
      >
        <input
          type="text"
          value={draftMsg}
          onChange={(e) => setDraftMsg(e.target.value)}
        />
        <button type="submit">Submit</button>
      </form>
    </>
  );
};

renderCalderaApp(<App />, { port: 4000 });

Install Babel by running npm install @babel/core @babel/node @babel/preset-react .

Then, run the app using babel-node --presets @babel/preset-react index.jsx . For a runnable version, check the basic-example folder.

A few other examples here demonstrate features like shared state, database usage, and session persistence.

API/Documentation

[Work in progress]

The caldera package provides the following top-level exports:

  • Head : A React component that renders its children into the page's <head />
  • renderCalderaApp : A function that takes in a React element, and runs the Caldera server on port 8080
  • makeSharedResource : Creates a shared resource suitable for use in useSharedState and useSharedReducer
  • useSharedState / useSharedReducer : Shared equivalents to the useState and useReducer hooks that are initialized with the current value of the passed in resource, and trigger rerenders in all other call sites upon updating
  • useHistory / useLocation - hooks that enable routing functionality

What works

<Head />

What's being worked on

<input type="file">

Future plans

  • Proper versioning for state serialization
    • This will allow support for upgrading the server in-place, while retaining certain parts of the client state
  • Support for selectively rendering arbitrary React components on the client

以上所述就是小编给大家介绍的《Caldera – Phoenix LiveView for Node and React》,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持!

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