chain-promises-2.js

function doSomething() {
    const results = {};
    return performStep1()
        .then(result1 => (results.one = result1))
        .then(() => performStep2(results.one))
        .then(result2 => (results.two = result2))
        .then(() => performStep3(results.two))
        .then(result3 => performFinalStep(results.one, result3))
        .then(finalResult => ({
            result2: results.two,
            finalResult,
        }));
}