promise-all-sync.js

function allSequential(promiseFns) {
    const initPromise = Promise.resolve([]);
    return promiseFns.reduce(_chainPromise, initPromise);
 
    function _chainPromise(acc, pFn) {
        return acc.then(result => pFn().then(pResult => [...result, pResult]));
    }
}
 
allSequential([
    () => task1(),
    () => task2(),
    () => task3()
]).then(...) // then and catch behaves as Promise.all