Get async value and send to another module

Question

How can I send res.data.values to another module.js? And how can I get it in module.js? The code below is a piece of the code provided by the following link: https://developers.google.com/sheets/api/quickstart/nodejs

The res.data.values take some time to response, so I believe this is my main problem and I don't know how to handle this.

function listMajors(auth) {
  const sheets = google.sheets({version: 'v4', auth});
  sheets.spreadsheets.values.get({
    spreadsheetId: '1XrmHL0D8HCulZYaB_ocrYlpnvqP9cO0BTJ14wHTGLis',
    range: 'Ficha',
  }, (err, res) => {
    if (err) return console.log('The API returned an error: ' + err);
    const rows = res.data.values;
    if (rows.length) {
      console.log(rows)
    } else {
      console.log('No data found.');
    }
  });
}

user_1594359 · Answer

If I understand your problem correctly. You are looking for a solution for async data handling. There are many ques/answers you can find over the internet. But just to help fast, Please refer to the below answer.

//List.js
// Using callback

function listMajors(auth, cb) {
  const sheets = google.sheets({ version: "v4", auth });
  sheets.spreadsheets.values.get(
    {
      spreadsheetId: "1XrmHL0D8HCulZYaB_ocrYlpnvqP9cO0BTJ14wHTGLis",
      range: "Ficha",
    },
    (err, res) => {
      cb(err, res.data.values.length ? res.data.values : []);
    }
  );
}
exports.listMajors = listMajors;


// main.js
// in other module
const { listMajors } = require("./List");

listMajors("auth", (error, rows) => {
  if (error) {
    /// show error message
  } else if (rows.length) {
    // display rows
  } else {
    //display empty
  }
});

Since Google sheets provide promisable method. You can simplify using async-await or promises. Below is an example using async-await. You can simply use `promise-then

// Using async-await

//List.js

async function listMajors(auth) {
  const sheets = google.sheets({ version: "v4", auth });
  try {
    const res = await sheets.spreadsheets.values.get({
      spreadsheetId: "1XrmHL0D8HCulZYaB_ocrYlpnvqP9cO0BTJ14wHTGLis",
      range: "Ficha",
    });
    return res.data.values.length ? res.data.values : [];
  } catch (error) {
    throw error;
  }
}

exports.listMajors = listMajors;

// main.js

const { listMajors } = require("./List");

// in other module
async function main() {
  try {
    const rows = await listMajors("auth");
    if (rows.length) {
      // display rows
    } else {
      //display empty
    }
  } catch (error) {
    /// show error message
  }
}

main();

user_7075830 · Answer

The problem that you described can be solved with the pub-sub architecture:

There are many libraries that can achieve this, like Redis:

const express = require("express")
const redis = require("redis")
const subscriber = redis.createClient()
const app = express()
subscriber.on("message", (channel, message) => {
  console.log("Received data :" + message)
})

app.get("/", (req, res) => {
  res.send("subscriber two")
})

subscriber.subscribe("user-notify")
app.listen(3007, () => {
  console.log("server is listening to port 3007")
})

Get async value and send to another module

2 Answers