AI Chat

概要

核心数据结构： 消息列表 (messages)

核心操作：调用模型接口，生成消息

次要操作：复制、引用、重新生成、编辑、参考附件选择

UI：聚合上操作以及数据

class CoreUI {
    useMessage(){
        // connect to message
        return this
    }
    useHandle(){
        // connect to handle
        return this
    }
    useChat(){
        // connect to AI
        return this
    }
    render(){
        // render ui
        return <></>
    }
}
new CoreUI().useMessage().useHandle().useChat().render();

Concept

S-S-E

Server-Send-Event: data is flowing from server to client format: tag:string for example:

data: "{ name: 'marvin', age: 20 }"

在SSE中 数据以固定的格式传输到客户端，在使用之前客户端或许需要先进行解析。

Parse Data from string message

可以直接使用 fetch-event-source 来处理SSE格式的数据，其核心原理类似下面：

const textDecoder = new TextDecoder()
export async function* SSEMessageGenerator<T>(stream: ReadableStream) {
    if (!stream) {
        return
    }

    // @ts-ignore ReadableStream is not iterable in typescript
    for await (const chunk of stream) {
        const sse_chunk = textDecoder.decode(chunk); // may be multi-line
        let rest_str = ""
        // 使用for...of 替代 forEach，确保yield在生成器体内
        for (const line of sse_chunk.split(/\n+/)) {
            const json_str = line.replace(/data:\s*/, '').trim();
            if(json_str.length > 0) {
                try {
                    const message = JSON.parse(rest_str + json_str);
                    rest_str = "";
                    yield message as T; // 在生成器内yield消息
                } catch (e) {
                    rest_str += json_str
                    console.log("e => ", { e, rest_str });
                }
            }

        }

    }
}

const response = await fetch('');
for await (const message of SSEMessageGenerator<{ id: string }>(response.body)) {
    console.log(message)
}

SSEMessageGenerator的作用是将数据从 ReadableStream 中解析出来，并返回一个生成器。可以通过迭代这个生成器来获取更加详细的数据。

Design

Message

class Message {
    id: string;
    content: string
}
class MessageManager {
    #messages: Message[]
    appendMessage(message: Message){
    }
    replaceMessage(oldMessage: Message, message: Message){
    }
    updateMessage(message: Message){
    }
    removeMessage(message: Message){
    }
    getMessages(){
        return [] as Message[]
    }
    copyMessage(message: Message){}
    shareMessage(message: Message){}
    citeMessage(message: Message){}
}

Convert to react hook

import {useState} from "react";

interface Message {
    id: string;
    content: string
}
const useMessage = () => {
    const [messages, setMessages] = useState<Message[]>();

    /** useCallback is not necessary in react 19 */
    function appendMessage(message: Message){
        setMessages(prev => prev.concat(message));
    }

    function getMessages(){
        return messages;
    }
    return {
        messages,
        appendMessage,
        getMessages
    }
}

Handle

import {useState} from "react";

class Message {
    id: string;
    content: string
}

export default function () {
    const [citeMessage, setCiteMessage] = useState<Message>();
    const [loading, setLoading] = useState(false)

    async function* onRe(message: Message) {
        for (const msg of message.content) {
            yield {
                id: message.id,
                content: msg
            }
        }
    }

    function onCopy(message: Message) {
        navigator.clipboard.writeText(message.content).then(() => {
            alert('copied to clipboard')
        });
    }

    function onCite(message: Message) {
        setCiteMessage(prev => {
            if (prev?.id === message.id) {
                return undefined
            }
            return message
        });
    }

    return {
        onRe,
        onCopy,
        onCite,
        setLoading,
        loading,
        citeMessage,
    }
}

AI

export default function useChat() {
    async function* send(value: string, {} = {}) {
        yield 'hello'
        yield 'world'
        yield '!'
    }
    return {
        send
    }
}

UI

// @ts-ignore
import { useMessage, useHandle, useChat } from 'your-components'

function Chat(){
    const {  messages } = useMessage();
    const {  copy } = useHandle();
    const {  send } = useChat();

    return <>
        Your Ui
    </>
}