Cascading Async/Await Delay against an Array - Node.js

cascadeDelay.js

// slight modification and re-application of daliborgogic/delay.js
const timeout = ms => new Promise(res => setTimeout(res, ms));

// index is the index of an array member
async function throttle(index){
    console.log(`Index ${index} will fire after ${1500*index}ms`);
    return timeout(index*1500);
}

// let's say you have an async operation that makes requests to certain endpoints
// that you've wrapped in a new Promise
let requestResponses = 
    urls.map(url=>{
        return new Promise((resolve, reject) =>{
            // now for each array member you are cascading the timeout
            throttle(urls.indexOf(url))
                .then(()=>{
                  // do something async here such as making a request using request-promise-native, axios, etc.
                  // since you are cascading your timeout using the index there is exactly 1.5ms between each call
                  request.get(url)
                    .then(data=>{
                      resolve(data);
                    });
                });
         });
    });

Promises.all(requestResponses)
  .then(responses=>console.log(responses));

Slight modification and re-application of daliborgogic/delay.js