Greetings! In my current project, I am trying to introduce a 50ms delay before each subsequent HTTP request is sent to the server. Additionally, I aim to incorporate a functionality that triggers after all requests have been successfully made.
To better explain my intentions, here's an example illustrating what I'm aiming for:
Below you'll find an example of an Express API that I've put together:
app.get('/morans/test', (req, res) => {
console.log(`start test request`);
let targetUrl = `http://-domain-/solr/genea_expression/smplGeoclust?q=text:"GO:0003674"&stats.facet=geohash_3&rows=10320`;
let i = 0;
let promises = [];
console.log(`making request ${i}`);
for (let i = 0; i < 200; i++) {
setTimeout(
() => {
let testReq = new Promise((resolve, reject) => {
http.get(targetUrl, (result) => {
result.on('data', (chunk) => {
console.log(`working ${i}`);
}).on('end', () => {
console.log(`ending ${i}`);
}).on('error', (err) => {
console.log(`this is error message ${err}`);
})
})
});
promises.push(testReq);
}, 50 * i
)
}
Promise.all(promises).then(() => {
console.log(`done`);
});
});
Although the delay functions correctly, there seems to be an issue with the Promise.all(promises)... statement as it triggers prematurely (console.log('done') appears once the first request is sent). Without any timeout, everything runs smoothly. My suspicion is that the setTimeout function doesn't provide enough time for the promise to be added to the promises array. How can I adjust the code so that each HTTP request is spaced 50ms apart and still know when all requests have been completed successfully?