00. Resouce.js

//Dummy resource
var Resource = {

    open: function() {

        var res = {
            read: function() {
                return new Promise(function(_resolve, _reject) {
                    setTimeout(function() {
                        _resolve('hogeeee');
                        //return _reject('read error!');
                    }, 1000);
                });
            },
            close: function() {
                console.log('Resource is closed.');
            }
        };

        return new Promise(function(resolve, reject) {
            setTimeout(function() {
                console.log('Resource is opened.');
                return resolve(res);
                //reject('open error!');
            }, 1000);
        });
    }
};

01. main.js

(async ()=> {
    const res = await Resouce.open("path"); 
    
    try{
        const result = await res.read();
        
        console.log(result);
    }
    finally{
        res.close();
    }
})().catch((err)=> console.error((err&&err.stack) || err));