Lazy load google maps dynamic script injector

gmapLoader.js

import { loadScript } from './scriptLoader';

export class GoogleMapScriptLoader {
    static instance;
    url;
    promise;

    constructor(){
        if(GoogleMapScriptLoader.instance){
            return GoogleMapScriptLoader.instance 
        }
        this.url = `https://maps.googleapis.com/maps/api/js?key=<google maps api key>`;
        GoogleMapScriptLoader.instance = this;
    }

    static getInstance(){
        return new GoogleMapScriptLoader();
    }

    async loadGoogleMapLib(){

        if (typeof google !== 'undefined' && google.maps) {
            return Promise.resolve(google.maps);
        }

        try {
            if (!this.promise) {
                this.promise = loadScript(this.url);
            }
            await this.promise;
            return Promise.resolve(google.maps);
        } catch (err) {
            console.error(err);
            return Promise.reject(err);
        }
    }

}

scriptLoader.js

export const loadScript = async (url, type = 'text/javascript') => {
    return new Promise((resolve, reject) => {
        const script = document.createElement('script');
        script.type = type;
        script.src = url;

        script.onload = resolve;
        script.onerror = reject;
        script.async = true;

        document.body.appendChild(script);
    });
};