npm install once-done

var onceDone = require('once-done');

var file = getFile();

var someResultPromise = handleFileAsync(); //someStatsPromise may be rejected

onceDone(someResultPromise, function () {
    file.close(); //Close the file in any situation
    return file.deleteAsync(); //You may return Promise, and it will be resolved!
})
.then(function (result) {
    //Handle the result
})
.catch(function (reason) {
    //Check a reason of rejection
});