How to delay between each axios call - http

Question

I need to put some delays between each axios POST call so POST calls are in sequence -- wait one finishes before issue the next POST.
The delay code I put in seems to delay -- console log shows "Delaying" and pauses there for some seconds, but on the server side, POST calls are still concurrent.
import * as Axios from "axios";
delay(delayTime:number) {
var tNow = Date.now();
var dateDiff = 0;
do {
dateDiff = Date.now() - tNow;
} while (dateDiff < delayTime); //milliseconds
}
// the code below is in a for loop
let axiosConfig = {
url: myurl,
method: ‘POST’,
timeout: 5,
headers: {
'Authorization' : AuthStr,
'Accept' : 'application/json',
'Content-Type' : 'application/json'
},
data: objContent
}
console.log(">>>>>>>>>>>>>>>>>>> Delaying”);
delay(10000);
let request = Axios.create().request(axiosConfig).
catch((rejection:any) => {
// some code
});

Answer 1

In order to wait one HTTP request finishes before issue the next request, you need to queue the HTTP request (queue async operation). The steps are:
When HTTP request is needed, add it to the queue.
Check whether there are any elements in the queue. If any, pick up one and execute it.
After that HTTP request is finished, goto step 2.
Example code would look like below:
const axios = require('axios');
let queue = [];
function sendRequest(callback) {
axios.get('http://example.com')
.then(function() {
callback();
}).catch(function () {
callback();
});
}
function addRequestToQueue() {
let id = (Math.random()*100000).toFixed(0);
if (queue.length === 0) {
sendRequest(function() {
queue.splice(queue.indexOf(id), 1);
consumeQueue();
});
}
queue.push(id);
}
function consumeQueue() {
if (!queue.length) {
return;
}
let id = queue[0];
sendRequest(function() {
queue.splice(queue.indexOf(id), 1);
consumeQueue();
});
}
addRequestToQueue();
addRequestToQueue();
addRequestToQueue();
addRequestToQueue();
addRequestToQueue();