delay in between chain of promises - node.js

Question

everyone, I have been trying out a delay of 8secs within the chain of promises i.e promise.all.
But unfortunately, it's not executing the way I want it to execute it.
I want a delay of 8secs between an array of promises and I have tried out some code. Anyone any idea how to put it or where I am going wrong?
var cron = require('node-cron');
let cron_schedule="* * * * *";
let max_Request = 10,requestProcess = [];
let checkCronJob = () => {
while (max_Request > 0){
requestProcess.push(processRequest(produce))
requestProcess.push(delay(8000));
}
return Promise.all(requestProcess).then((result) => {
console.log(result);
});
}
var delay = function () {
var promise = new Promise((resolve, reject) => {
setTimeout(() => {
resolve(true)
}, 8000);
});
return promise;
}
let processRequest = async (produce) => {
max_Request--;
return await Promise.resolve(true);
}
checkCronJob();
"processRequest" will return a promise and after that, I added a delay of 8secs but it is actually executing all the promises in one go after a delay of 8secs.
I wanted the promises to execute within the delay of 8secs.

Answer 1

For what you want to do:
var delay = promise => {
return new Promise((resolve, reject) => {
promise.then(() => {
setTimeout(() => {
resolve(true)
}, 8000);
});
});
}
var recursiveDelay = n => {
delay(processRequest(produce)).then(() => { if(n > 0) recursiveDelay(n-1)});
}
recursiveDelay(10);

Answer 2

Promises are executed immediately, if you want to ensure a delay before starting the next action then you can't setup the promises like you are.
You would need to do something like:
while (max_Request > 0) {
await processRequest(produce);
await delay(8000);
max_Request--;
}
If you can't use async / await, then it's slightly uglier
let req;
while (max_Request > 0) {
if (!req) {
req = processRequest(produce);
} else {
req.then(processRequest(produce));
}
req.then(delay(8000));
max_Request--;
}
return req.then(console.log);