Promise.all ignoring errors

gistfile1.js

// Reject if every promise fails, otherwise resolve 
// with the values which resolved, ignoring errors.
// Inspired by https://github.com/slightlyoff/ServiceWorker/issues/359
function allThatResolve(promises) {
		var results = [],
			seen    = 0,
			length  = promises.length;
	
	function done(resolve, reject) {
		seen++;
		if (seen === length) {
			if (results.length) {
				resolve(results);
			} else {
				reject('all failed');
			}
		}
	}
	
	return new Promise(function(resolve, reject) {

		promises.reduce(function(chain, promise, index, array) {

			// Cast value to Promise
			promise = Promise.resolve(promise);

			promise.then(function(result) {
				results.push(result);
				done(resolve, reject);
			})
			.catch(function(error) {
				console.error('Ignoring error:', error);
				done(resolve, reject);
			});

			// Build a chain of promises, where each catches from the previous
			return chain.catch(function() {
				return promise;
			});

		}, Promise.reject());
	});
}

function timeout(val) {
	return new Promise(function(resolve, reject) {
		setTimeout(function() {
			val ? resolve(val) :reject('timeout');
		});
	});
}

// => PASS: [1, "hello", true]
allThatResolve([timeout(1), timeout('hello'), timeout(true)])
.then(function(results) {
	console.log('PASS:', results);
})
.catch(function(error) {
	console.log('FAIL:', error);
})

// => PASS: [1, "hello"]
allThatResolve([timeout(1), timeout('hello'), timeout()])
.then(function(results) {
	console.log('PASS:', results);
})
.catch(function(error) {
	console.log('FAIL:', error);
})

// => FAIL: all failed
allThatResolve([timeout(), timeout(), timeout()])
.then(function(results) {
	console.log('PASS:', results);
})
.catch(function(error) {
	console.log('FAIL:', error);
})

Better: https://gist.github.com/jakearchibald/201eb256be3ff6dac1d8