export and import firestore document tree (typescript). env var GOOGLE_APPLICATION_CREDENTIALS must be defined before run

export_import_firestore_docs.ts

import {Firestore} from "@google-cloud/firestore";
import fs from "fs";
const firestore = new Firestore();
const keyOriginalPath = "__originalPath__";
const keyDocumentContent = "__documentContent__";
const keyCollectionPath = "__collectionPath__";
const keyCollections = "__collections__";
const keyDocument= "__document__";

if(process.argv.length !== 5){
    console.log('Please specify "mode", "firestore root path" and "output/input file name"');
    console.log(`USAGE: ${process.argv[0]} ${process.argv[1]} [export|import] root_path [output_file|input_file]`);
    process.exit(1);
}
const mode = process.argv[2];
const documentPath = process.argv[3];
const fileName = process.argv[4];

async function get_document_tree(path: string) {
    // console.log(`Get Tree ${path}`)
    const docRef = firestore.doc(path);
    const snapshot = await docRef.get();
    const docContent = await snapshot.data();
    const collectionRefs = await docRef.listCollections();
    const collectionIds = collectionRefs.map((c: any) => {return c.id});
    const collectionContents = [];
    for(const collectionId of collectionIds){
        const documents = await docRef.collection(collectionId).listDocuments();
        for(const document of documents){
            const documentTree:any = await get_document_tree(`${path}/${collectionId}/${document.id}`);
            collectionContents.push({[keyCollectionPath]:`${collectionId}/${document.id}`,[keyDocument]: documentTree});
        }
    }
    return {[keyOriginalPath]: path, [keyDocumentContent]: docContent, [keyCollections]: collectionContents};
}

async function do_export() {
    return await get_document_tree(documentPath);
}

async function create_document_tree(path: string, data:any){
    const docRef = firestore.doc(path);
    // console.log(`Importing data of ${data[keyOriginalPath]} to ${path}`);
    await docRef.set(data[keyDocumentContent]);
    for(const collectionDocument of data[keyCollections]){
        await create_document_tree(`${path}/${collectionDocument[keyCollectionPath]}`,
            collectionDocument[keyDocument])
    }
}
async function do_import(){
    const data = fs.readFileSync(fileName, "utf8");
    await create_document_tree(documentPath, JSON.parse(data));
}

if(mode==="export") {
    console.log(`Exporting ${documentPath} to ${fileName}`);
    do_export().then((result: any) => {
        const json = JSON.stringify(result);
        console.log(json);

        fs.writeFile(fileName, json, (err: any) => {
            if (err) console.log(`File output error : ${err}`);
        });
    }).catch((reason: any) => {
        console.log(`Export error by ${reason}`)
    });
}
else if(mode==="import"){
    console.log(`Importing ${fileName} to ${documentPath}`);
    do_import().then(() => {
        console.log("Completed.");
    }).catch((reason:any)=>{
        console.log(`Import error by ${reason}`)
    })
}
else{
    console.log(`invalid mode ${mode}`);
    process.exit(1);
}