Services with Angular 1.* and ES6

analytics.service.js

import BaseService from './base.service';

class AnalyticsService extends BaseService {
    constructor($http) {
        'ngInject';
        super(...arguments);
    }

    fetchSomething() {
        return this.$http.get('/api/analytics/something');
    }
}

export default AnalyticsService;

app.module.js

import angular from 'angular';
import AnalyticsService from './analytics.service';

angular.module('app', [])
    .service('Analytics', AnalyticsService);

base.service.js

class BaseService {
    constructor(...dependencies) {
        dependencies.forEach(dependency, dependency => this[dependency] = dependency);
    }
}

export default BaseService;