van-hmr/hmr.js

//@ts-check
// hmr
const HMR = globalThis.HMR = {
    Time: 0,
    /** @type {Record<string, string>} */
    Temp:{},
    Tick()
    {
        for(const k in HMR.Temp)
        {
            sessionStorage.setItem(k, HMR.Temp[k]);
        } 
        HMR.Temp = {};
        HMR.Time = 0;
    },
    /** @type {(key:string, value:string)=>void} */
    Save(key, value)
    {
        this.Temp[key] = value;
        if(!this.Time)
        {
            this.Time = setTimeout(this.Tick, 500);
        }
        console.log("SAVE", key, value);
    },
    /** @type {(key:string)=>string|null} */
    Load(key)
    {
        const value = sessionStorage.getItem(key);
        console.log("LOAD", key, value);
        return value;
    },

    /** @type {string|undefined} */
    _ID: undefined,
    _index: 0,
    /** @type {(id:string|undefined = undefined)=>void} */
    StartID(id)
    {
        this._index = 0;
        this._ID = id;
    },
    NextID()
    {
        return this._ID ? this._ID + "_" + (this._index++) + "_" : "";
    },

    BindVan()
    {
        //bind Van
        const origninalState = globalThis.van.state;
        globalThis.van.state =(value, key="")=>
        {
            const type = typeof value;
            let reader =d=>d;
            let writer =d=>d?.toString() || null;

            switch(type)
            {
                case "boolean" :
                    reader =(data)=> data === "true"; break;
                case "number" :
                    reader = parseFloat; break;
                case "object" :
                    reader = JSON.parse;
                    writer = JSON.stringify;
                    break;
            }

            const fullKey = "HMR_" + HMR.NextID() + key;
            const stringValue = HMR.Load(fullKey);
            const signal = origninalState(/**@type{T}*/(stringValue ? reader(stringValue) : value));
            van.derive(()=>HMR.Save(fullKey, writer(signal.val)));

            return signal;
        };
    },

    BindVanX()
    {
        //bind VanX
        const originalReactive = globalThis.vanX.reactive;
        globalThis.vanX.reactive =(obj, id)=>
        {
            HMR.StartID(id);
            const state = originalReactive(obj);
            HMR.StartID();
            return state;
        }
    }

}