expressjs returning controller object to res.send - node.js

Question

I have a controller that makes an api call (few seconds delay) and then returns a JSON object that I want to send and appear on my view page. At the moment I am able to return the object and successfully load the route, but the object is not appearing on my browser page (status code: 200) and I'm not sure what I might be missing. Provided below is my route and controller.
Controller:
var express = require('express');
var apiRouter = express.Router();
var googleAnalytics = require('../google-analytics');
const { checkToken } = require("./components/token-validator");
apiRouter.use(checkToken);
apiRouter.get('/ga', function(req, res){
res.send(googleAnalytics())
});
module.exports = apiRouter;
Controller (googleAnalytics):
module.exports = () => {
console.log("google-analytics.js")
const {google} = require('googleapis');
const analyticsreporting = google.analyticsreporting('v4');
const view_id = '*view-id(';
... // resource: req information
analyticsreporting.reports.batchGet({
resource: req
}, (err, result) => {
if(err){
if(err.errors){
console.log(err.errors[0].message)
} else {
console.log(err)
}
} else {
return result.data;
}
//console.log("BREAK IN CONSOLE")
//console.log(err, result)
})
}
Object E.g.:
{"reports":[{"columnHeader":{"dimensions":["ga:sourceMedium"],"metricHeader":{"metricHeaderEntries":
...
]}}

Answer 1

You are not returning anything from the google-analytics.js. You need to make the function return a promise or use callback. analyticsreporting.reports.batchGet returns a promise so it is pretty easy to do that.
module.exports = () => {
console.log("google-analytics.js")
const {google} = require('googleapis');
const analyticsreporting = google.analyticsreporting('v4');
const view_id = '*view-id(';
... // resource: req information
return analyticsreporting.reports.batchGet({
resource: req
});
}
Now, in your /ga route, you can use async-await:
apiRouter.get('/ga', async function(req, res){
res.send(await googleAnalytics())
});