Convert Firestore Timestamps to text format using javascript-time-ago. Works when Timestamps are retrieved both from client SDK or Cloud Functions. JS/ Typescript

getTimeText.tsx

import app from 'firebase/app'
import 'firebase/firestore'

import TimeAgo from 'javascript-time-ago'
// Load locale-specific relative date/time formatting rules.
import en from 'javascript-time-ago/locale/en'

// Add locale-specific relative date/time formatting rules.
TimeAgo.addLocale(en)

// Adapted from Andrey Gordeev's answer at: 
// https://stackoverflow.com/questions/56245156/timestamp-from-firestore-gets-converted-to-a-map-when-using-cloud-function

class MyClass {
    timeAgo: TimeAgo

    constructor() {
        this.timeAgo = new TimeAgo('en-US')
    }

    getTimeText = (timeObject: any) => {
        // Convert to time text once it's of type firestore.Timestamp
        const getTextFromTimestamp = (timestamp: app.firestore.Timestamp) => {
            return this.timeAgo.format(timestamp.toDate())

        }
        if (timeObject instanceof app.firestore.Timestamp) {
            // Check if Timestamp (accessed from client SDK)
            return getTextFromTimestamp(timeObject)
        } else if (Object.prototype.toString.call(timeObject) === '[object Object]') {
            // Check if it's a Map (accessed from Cloud Functions)
            const seconds = timeObject['_seconds']
            const nanoseconds = timeObject['_nanoseconds']
            if (seconds && nanoseconds) {
                const timestamp = new app.firestore.Timestamp(seconds, nanoseconds)
                return getTextFromTimestamp(timestamp)
            }
        }
        console.log('Couldn\'t parse time', timeObject)
        // Fallback
        return 'some time ago'
    }
}