Async Function that returns Array, when accessed, returns a non-iterable Object

Question

I have created a script meant to read data from a google sheet, the function getData() returns a promise of an Array. However, when I access the data afterwards, the value of the data is a promise of a function. Why is this the case?


import dotenv from "dotenv";
import { google } from "googleapis";
import { mainModule } from "process";

dotenv.config();

const spreadsheetID = process.env.spreadsheetID;

if (process.env.NODE_ENV == "production") {
  var fs = require("fs");

  fs.writeFile("./secrets.json", process.env.SECRET, (err: any) => {
    err;
  });
}

async function getData() {
  const auth = new google.auth.GoogleAuth({
    keyFile: "secrets.json",
    scopes: "https://www.googleapis.com/auth/spreadsheets",
  });

  const client = await auth.getClient();

  const googleSheets = google.sheets({ version: "v4", auth: client });

  var getRows = await googleSheets.spreadsheets.values.get({
    auth: auth,
    spreadsheetId: spreadsheetID,
    range: "Sheet1",
  });
  console.log(getRows.data.values);
  console.log(Array.isArray(getRows.data.values))
  return getRows.data.values;
}

const data = getData();

data.then(() => {
  console.log(Array.isArray(data);
    console.log(data);
    
  var present_list = (data as any).forEach((user: any) => {
    if (user[4] == "P") {
      present_list.append(user);
    }
  });
  console.log(present_list);
});

console.log("asdasd");

Does this answer your question? [How to access the value of a promise?](https://stackoverflow.com/questions/29516390/how-to-access-the-value-of-a-promise) — Wing, Sep 19 '21 at 22:04
`data` here is a promise, not your data itself. You need to do `data.then(yourArray => { ...})` and then use the vlaue of `yourArray`. — jfriend00, Sep 20 '21 at 06:39

score 0 · Answer 1 · answered Sep 19 '21 at 21:56

If we want to access the data from a promise, we would want to do something like this:

//...
const data = getData();

data.then((result) => {
  const present_list = result.forEach((user: any) => {
    ...
  });
});

We don't want to use the data variable, because obviously that would a promise, even inside the callback function passed to then. We would want to use the parameter of the callback, which will be have the data extracted from the promise.

Async Function that returns Array, when accessed, returns a non-iterable Object

1 Answers1