What is the difference between setting a property on app.locals and calling app.set()?

Question

I\'m in the process of learning Express - and thinking of the best place to save config style data. Options available are either in app.locals or app.set (settings)... so:

Answer 1

All properties of app.locals are available in templates. Using app.set assigns properties to app.locals.settings, which is used for global application settings and is inherited by mounted applications. For example:

var app1 = express(),
    app2 = express();

app1.set('inheritable', 'foo');
app1.locals.notInheritable = 'bar';

app1.use('/mount', app2);

app2.get('inheritable') === 'foo'; // true
app2.locals.notInheritable === 'bar'; // false

So it's really a question of preference and whether or not you're mounting applications.