promises + addInitializer

application.js

var Application = {
    addInitializer: function(func) {
        return new Promise(func);
    }
};

Promise.all([
    Application.addInitializer(require('./initializers/something')),
    Application.addInitializer(require('./initializers/something-else')),
    Application.addInitializer(require('./initializers/blah'))
]).then(function() {
    console.log('success', arguments);
}, function() {
    console.log('failure', arguments);
});

initializers__blah.js

module.exports = function(resolve, reject) {
    setTimeout(function() {
        resolve(new Error('C'));
    }, 1000);
};

initializers__something-else.js

module.exports = function(resolve, reject) {
   resolve('B');
};

initializers__something.js

module.exports = function(resolve, reject) {
    resolve('A');
};