Wait until all promises have completed even when some reject, with Promise.all

PromisAllWithFails.js

var a = ["sdfdf", "http://oooooolol"],
    handleNetErr = function(e) { return e };

Promise.all(fetch('sdfdsf').catch(handleNetErr), fetch('http://invalidurl').catch(handleNetErr))
    .then(function(sdf, invalid) {
        console.log(sdf, invalid) // [Response, TypeError]
    })
    .catch(function(err) {
        console.log(err);
    })

Promise.all(a.map(function(e) { 
    return fetch(e).catch(handleNetErr) 
})).then(function(e) { 
    console.log('then',e) // Outputs: 'then', [Response, TypeError]
}).catch(function(e) { 
    console.log('err',e) 
})

PromiseAllWithFails.es6.js

let a = new Promise((res, rej) => res('Resolved!')),
    b = new Promise((res, rej) => rej('Rejected!')),
    c = a.catch(e => { console.log('"a" failed.'); return e; }),
    d = b.catch(e => { console.log('"b" failed.'); return e; });

Promise.all([c, d])
  .then((first, second) => console.log('Then', first, second)) // Then ["Resolved!", "Rejected!"]
  .catch(err => console.log('Catch', err));

Promise.all([a.catch(e => e), b.catch(e => e)])
  .then((first, second) => console.log('Then', first, second)) // Then ["Resolved!", "Rejected!"]
  .catch(err => console.log('Catch', err));
  

Instead of using Promise.all() , you can use Promise.allSettled().
Refer: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/allSettled