Example 5-9. Use catch/then to mimic catch/finally

function getData() {
	var dataPromise;
	var timestamp = performance.now();

	dataPromise = new Promise(function (resolve, reject) {
		// ...
		throw new Error('Unexpected problem');
	});

	dataPromise.catch(function (err) {
		// Do not rethrow error
	}).then(function () {
		// Simulates finally block
		console.log('Data fetch took ' + (performance.now() - timestamp));
	});

	// Return data promise instead of catch/then tail to propagate rejection
	return dataPromise;
}