Demystifying Async Programming in Javascript - fetchJson promise

fetchJson-promise.js

fetchJson('/api/user/self')
    .then(function (user) {
        return fetchJson('/api/user/interests?userId=' + self.id);
    })
    .then(function (interests) {
        return Promise.all[interests.map(i => fetchJson('/api/recommendations?topic=' + i))];
    })
    .then(function (recommendations) {
        render(user, interests, recommendations);
    });