waffle/frontend/src/stores.js

import gateway, { GatewayEventType } from "./gateway";

export const channels = {
    _handlers: [],
    _value: [],
    _didInit: false,
    subscribe(handler) {
        this._init();

        const newLength = this._handlers.push(handler);
        const handlerIndex = newLength - 1;
        handler(this._value);
        return () => {
            this._handlers.splice(handlerIndex, 1);
        };
    },
    _dispatchUpdate() {
        this._handlers.forEach(e => {
            e(this._value);
        });
    },
    _init() {
        window.__WAFFLE_CHANNELS_STORE = this;

        if (this._didInit)
            return;

        this._didInit = true;

        const channels = gateway.channels;
        if (channels) {
            this._value = channels;
        }

        gateway.subscribe(GatewayEventType.Ready, ({ channels }) => {
            if (channels) {
                this._value = channels;
            }

            this._dispatchUpdate();
        });
        gateway.subscribe(GatewayEventType.ChannelCreate, (channel) => {
            this._value.push(channel);

            this._dispatchUpdate();
        });
        gateway.subscribe(GatewayEventType.ChannelDelete, ({ id }) => {
            const index = this._value.findIndex(e => e.id === id);
            if (!index)
                return;

            this._value.splice(index, 1);

            this._dispatchUpdate();
        });
        gateway.subscribe(GatewayEventType.ChannelUpdate, (data) => {
            const index = this._value.findIndex(e => e.id === data.id);
            if (!index)
                return;

            if (!this._value[index])
                return;

            this._value[index] = data;

            this._dispatchUpdate();
        });
    }
};