Ignore firebase.firestore.timestamp - firebase

Question

My project used #Nativescript/firebase(https://github.com/EddyVerbruggen/nativescript-plugin-firebase) ignores methods of firebase.firestore.timestamp, and returns undefined by properties.
The below is minimum reproduction
app.js
import Vue from "nativescript-vue";
import Home from "./components/Home";
var firebase = require("#nativescript/firebase").firebase;
firebase
.init({})
.then(
function () {
console.log("firebase.init done");
},
function (error) {
console.log("firebase.init error: " + error);
}
);
new Vue({
render: (h) => h("frame", [h(Home)]),
}).$start();
Home.vue
import { firebase } from "#nativescript/firebase";
export default {
computed: {
async message() {
const Ref = firebase.firestore
.collection("comments")
.doc("07bhQeWDf3u1j0B4vNwG");
const doc = await Ref.get();
const hoge = doc.data();
console.log("hoge.commented_at", hoge.commented_at); // CONSOLE LOG: hoge.commented_at Sat Oct 23 2021 22:44:48 GMT+0900 (JST)
console.log("hoge.commented_at.seconds", hoge.commented_at.seconds); // CONSOLE LOG: hoge.commented_at.seconds undefined
const hogeToDate = hoge.toDate();
console.log("hogeToDate", hogeToDate); // no console.log appear
return hogeToDate; // simulator shows "object Promise"
},
},
};
I also tried const hogeTimestampNow = firebase.firestore.Timestamp.now(); then no console.log appear...
Environment
vue.js
Node.js v14.17.6
nativescript v8.1.2
nativescript-vue v2.9.0
#nativescript/firebase v11.1.3

Answer 1

If you dive into the source of #nativescript/firebase, in particular looking at /src/firebase-common.ts, you can see that firebase is a custom implementation and not the object/namespace normally exported by the ordinary Firebase Web SDK.
It uses a custom implementation so that it can be transformed depending on the platform the code is running on as shown in /src/firebase.android.ts and /src/firebase.ios.ts.
Of particular importance, is that Firestore's Timestamp objects are internally converted to JavaScript Date objects when exposed to your code as each platform has its own version of a Timestamp object. Because the exposed JavaScript Date object doesn't have a seconds property, you get undefined when attempting to access hoge.commented_at.seconds.
The equivalent of Timestamp#seconds would be Math.floor(hoge.commented_at / 1000) (you could also be more explicit with Math.floor(hoge.commented_at.getTime() / 1000) if you don't like relying on JavaScript's type coercion).
function getSeconds(dt: Date) {
return Math.floor(dt.getTime() / 1000)
}
While you can import the Timestamp object from the Modular Web SDK (v9+), when passed into the NativeScript plugin, it would be turned into an ordinary object (i.e. { seconds: number, nanoseconds: number } rather than a Timestamp).
import { Timestamp } from 'firebase/firestore/lite';
const commentedAtTS = Timestamp.fromDate(hoge.commented_at);
docRef.set({ commentedAt: commentedAtTS.toDate() }) // must turn back to Date object before writing!

Answer 2

firebase.firestore.timestamp does not work via #nativescript/firebase as #samthecodingman said.(https://stackoverflow.com/a/69853638/15966408)
Just use ordinally javascript methods and edit.
I tried
get timestamp from firestore then convert to milliseconds
get date with new Date() then convert to milliseconds
and same miliseconds logged.
via firestore
const Ref = firebase.firestore.collection("comments").doc("07bhQeWDf3u1j0B4vNwG");
const doc = await Ref.get();
const hoge = doc.data();
console.log("hoge.commented_at in milliseconds: ", Math.floor(hoge.commented_at / 1000));
// CONSOLE LOG: hoge.commented_at in milliseconds: 1634996688
via javascript methods
const getNewDate = new Date("October 23, 2021, 22:44:48 GMT+0900");
// same as hoge.commented_at
console.log("getNewDate in milliseconds: ", getNewDate.getTime() / 1000);
// CONSOLE LOG: getNewDate in milliseconds: 1634996688