Checking firebase initialization

firebase.js

// basic checking
// if (firebase.apps.length === 0) {
//   firebase.initializeApp({
//     // ... firebase config
//   })
// }

// node module
// example named file: firebase.js
/**
 * Firebase
 * singleton design pattern
 */
var firebase = require('firebase');
var config = {
    apiKey: "___"
    // ... and so on (firebase config)
};
firebase.initializeApp(config);

function getInstance() {
    console.log('getting firebase instance');
    if (firebase.appslength === 0) {
        console.log('firebase not yet initialized, initializing, firebase apps length:', firebase.apps.length, firebase.apps);
        firebase.initializeApp(config);
    } else {
        console.log('firebase already initialized, use existing', firebase.apps.length, firebase.apps);
    }
    return firebase;
}

module.exports = {
    getInstance: getInstance
};

// usage
// var firebase = require('./firebase').getInstance();