Comparison of function style, Ramda & flattening

await-unnest.js

async function displaySteamApps() {
    const paths = await getSteamAppsPaths();
    const appIdLibraries = await Promise.all(paths.map(getSteamAppIds));
    const appIds = Array.prototype.concat.apply([], appIdLibraries);
    const appsData = appIds.map(getSteamAppInfo);

    appsData.forEach(function (appData) {
        Promise.resolve(appData).then(renderSteamApp);
    });
};
displaySteamApps();

ramda-unnest.js

// Ramda + unnest
getSteamAppsPaths()
    .then(paths => Promise.all(paths.map(getSteamAppIds)))
    .then(R.unnest)
    .then(R.map(getSteamAppInfo))
    .then(R.forEach(function (appData) {
        Promise.resolve(appData).then(renderSteamApp);
    }));

ramda.js

// Ramda
getSteamAppsPaths()
    .then(paths => Promise.all(paths.map(getSteamAppIds)))
    .then(R.map(R.map(getSteamAppInfo)))
    .then(R.forEach(R.forEach(function (appData) {
        Promise.resolve(appData).then(renderSteamApp);
    })));

vanilla-arrow-unnest.js

// Vanilla arrow style + unnest
getSteamAppsPaths()
    .then(paths => Promise.all(paths.map(getSteamAppIds)))
    .then(appIdLibraries => {
        return Array.prototype.concat.apply([], appIdLibraries);
    })
    .then(appIds => appIds.map(getSteamAppInfo))
    .then(appsData => {
        appsData.forEach(function (appData) {
            Promise.resolve(appData).then(renderSteamApp);
        });
    });

vanilla-function.js

// Vanilla function style
getSteamAppsPaths()
    .then(function (paths) {
        return Promise.all(paths.map(getSteamAppIds));
    })
    .then(function (appIdLibraries) {
        return appIdLibraries.map(function (appIds) {
            return appIds.map(getSteamAppInfo);
        });
    })
    .then(function (appDataLibraries) {
        return appDataLibraries.forEach(function (appsData) {
            appsData.forEach(function (appData) {
                Promise.resolve(appData).then(renderSteamApp);
            });
        });
    });