typescript-async-constructor.ts

// https://www.typescriptlang.org/play/?#code/MYewdgziA2CmB0w4EMBOAKAlAKG6SALgAQAkyEAnmMAJJgCWxAvEQMoUC2ARjOgOQB9AeSrAB9BgQGUOfHPgjESExgCVYyACYUiLdt16DhlauMkDU2uXnCLSwVBoKwAcrADuutpx7R+QkVMHJ1gBMA9rPGhyCCIAIXJYIgBvbCJ0okVkAnpgTJ8YOjUNbS8sXQA+UhUCdS0KAG40jKycvMDaSX1fMsxK0g6igiaMzIJs3PyDaABhR2zXD17+kmCFt3cm5vTWyY6iAG1V+ecNgF1y1NHRxwIAV1QwInDPAgALeggsI5q67TPtkQAL64UYAB1Q9AAbgtDmQTJ1GGcAFxEcpMKoABVQIA4n1gAB5kGAKFUAD5EbG4-EEqEgeiaCqAiHQ2E-SR-Cgoyk4vEQQnE0mgjIKAioO7AAggDB9K7XdLvT5HQaSM7LDE86n8+COABWsEl-A4dzswGQ0GgREVEHgNQA6ow3qwpahkABzWDlCREUXiyXSgCE1nlCo+EHZxXqapYVL5CEcUGgUM9ADNzfycKMQYD9vbHc7pe7PWaLVxkMAANao9CabLIVEEChg2AgFNWsN9DWxml0hkVWWA0bWiO1EpcrwvTVx9D7dAJmDJgA0RD1BoInaqcpDItsxGbqAgn2cmgAInWvMlnsgOLBUXxQNAJHxgURyK+SYOQ8h3MhGD7zdAZaVug+6HoosCnnWmbbhk85Jp61rQfKQJIcC2DZlEMREAAsiAmiwJasAAB7OGAmixAk-IpICzI4s4koQUQtbjKigrCukvoSi6lyfjsdz7lgvHtp8tqSA67wFq6HozgiaKgUeEFnuMG7UTBO6QDACDQCAbr8PJ4GQeMfDLvpx5KcgqFZqh2ajPyBDmSBaA5Oa5mopiTn0OaRIklULDJChqkhta8DMcgF5EPAkXBaFy6RfAYIeS554gtutwPE80V1oCILZvsKZ3NQOTgEQ2laAAYryklFjxNywPcjzPEs3b8ugc6wImyYqVu1yOAAjnc7UEAAggwHATOAFXXp66KbkJtUdZ6l6haiACMABMADMy6fAAomAyBcHAmgNuKsDLvtN53g+T7ApZGQodlODZqKmpERQuH4ZaLCTlSb3oB9BHLt1+ycYaA6pXV6Wvj+f4A9ARxrKcHgXNZ6F9G+BUVmAIDuE8b7dS8WBubyNJw0yNnYHlBWSvQxVjRINXqXYEhZNQSQsN+v7ED9OJvXDgmAiz4xs-AdkOd1owXbeRB8M4yBvMSfCPexPq2Jp8DabpQvEsAsA4OhuD02AgkKOrmtGr+YB7ZochAA

console.clear()

const $asyncInit = Symbol('__async_init_sym')
const $initReady = Symbol('__async_init_rdy')
const $createNew = Symbol('__async_create_new')

class Base {
    static symbolInitReady = () => $initReady;
    static asyncInitSymbol = () => $asyncInit;
    static symbolCreateNew = () => $createNew;

    static async [$createNew]() {
        return new this()[$initReady]
    }

    private [$asyncInit]: () => Promise<any> | Promise<void>
    private [$initReady]: Promise<any>

    constructor() {
        this[$asyncInit] = () => Promise.reject('must call this.initWithStorage() in constructor!')
        this[$initReady] = Promise.resolve(false)
    }

    async initWithStorage(callback: (data: typeof this) => Promise<void>) {
        this[$initReady] = new Promise(async (resolve, reject) => {
            const persistedData = { name: 'colin' } as any
            await callback(persistedData)
            resolve(this)
        })
    }
}


class Model extends Base {
    
    protected data: any

    constructor() {
        super()
        this.initWithStorage(async (persistedData) => {
            console.log('persistedData', persistedData)
        })
    }

    setData(partialData: Partial<any> = {}) {
        this.data = { ...this.data, ...partialData }
        return this.data
    }
}

async function loadFromStorage() {
    return new Promise((resolve) => {
        requestAnimationFrame(() => {
            resolve({ data: 123, isEnabled: true, name: 'colin' })
        })
    })
}

const ProxyModel = new Proxy(Model, {
    async construct() {
        return await Model[$createNew]()
    }
}) as unknown as {
    new(): Promise<Model>
}

 
async function main() {
    const instance = await new ProxyModel()

    instance.setData({
        name: 'teahan'
    })

    console.log(instance)

}

main()
console.log('mainEnd')