Delays between promises in promise chain

Question

Let\'s say I am using the following code to run a couple of promises in series:

let paramerterArr = [\'a\',\'b\',\'c\',\'d\',\'e\',\'f\']
parameterArr.reduce         


        

Answer 1

The following shows an example of how you might achieve a promise that doesn't block but waits for a designated time period:

function timedPromise(ms, payload) {
    return new Promise(function(resolve) {
        setTimeout(function() {
            resolve(payload);
        }, ms);
    })
}


var time = Date.now();

timedPromise(1000)
    .then(function() {
        console.log(time - Date.now());
        return timedPromise(2000);
    }).then(function() {
        console.log(time - Date.now());
        return timedPromise(3000);
    });

So, depending on exactly what you want, you should be able to do something like this:

let paramerterArr = ['a','b','c','d','e','f']
parameterArr.reduce(function(promise, item) {
  return promise.then(function(result) {
    return mySpecialFunction(item);
  }).then(function(specialResult) {
    return timedPromise(50, specialResult);
  });
}, Promise.resolve())