nodejs async/await nested API progress - node.js

Question

I have an API that searches for the user-provided term, returns an array of results, then fires off async requests for each of the results and gets results for each of these second batch of requests. I'd like the API to report progress as it happens rather than just the final result. So, if I do the following request, I should get updates like so
$ curl 'http://server/?q=foobar'
searching for ${q}…
found 76… now getting images…
found 30 images… done
{
result
}
Most of relevant code is shown below. Fwiw, I am using hapijs for my application.
let imagesOfRecords = {};
const getImages = async function (q) {
console.log(`searching for ${q}…`);
const uri = `http://remoteserver/?q=${q}`;
const {res, payload} = await Wreck.get(uri);
const result = JSON.parse(payload.toString()).hits;
const numOfFoundRecords = result.total;
if (result.total) {
console.log(`found ${result.total}… now getting images…`);
const foundRecords = result.hits.map(getBuckets);
Promise.all(foundRecords).then(function() {
console.log(`found ${Object.keys(imagesOfRecords).length} images… done`);
reply(imagesOfRecords).headers = res.headers;
}).catch(error => {
console.log(error)
});
}
else {
console.log('nothing found');
reply(0).headers = res.headers;
}
};
const getBuckets = async function(record) {
const { res, payload } = await Wreck.get(record.links.self);
const bucket = JSON.parse(payload.toString()).links.bucket;
await getImageFiles(bucket, record.links.self);
};
const getImageFiles = async function(uri, record) {
const { res, payload } = await Wreck.get(uri);
const contents = JSON.parse(payload.toString()).contents;
imagesOfRecords[record] = contents.map(function(el) {
return el.links.self;
});
};
Once I can implement this, my next task would be to implement this progressive update in a web app that uses the above API.

Answer 1

To show result with each step of your requests for backend you can use EventEmitter, which will emit event on each progress step. You can read about events here.
Simple implementation:
const events = require('events');
const eventEmitter = new events.EventEmitter();
//your request code
Promise.all(foundRecords).then(function() {
console.log(`found ${Object.keys(imagesOfRecords).length} images… done`);
eventEmitter.emit('progress');
reply(imagesOfRecords).headers = res.headers;
})
const eventReaction = (e) => {
// do something with event, console log for example.
}
eventEmitter.on('progress', eventReaction);
More examples you can find here and here.
To show events to client you can use library socket.io. I think you can find pretty straightforward explanations how socket.io works in documentation.
If you want to send events between servers or processes and want to go little further, you can read more about 0MQ (zero mq) and it's node implementation