Objective
Pass the role (e.g. admin) of a user to all my view templates without having to do it in each individual route.
What I'm trying
Adding user roles (called with req.oidc.user...) as a res.local in app.js.
Code (app.js)
app.use((req, res, next) => {
res.locals.role = req.oidc.user['https://localhost:3000.com/roles'] ?? "null"
})
Problem
I was hoping the ?? "null" would add a value of "null" to the roles when a user is not logged in so I can handle conditional logic in the templates with
'if !role === 'admin' do x.
Instead, I'm just getting an error of Cannot read properties of undefined (reading 'https://localhost:3000.com/roles') (understandable as there's nothing there when not logged in!)
Is there a better way to pass a values that will be undefined until a user logs in to my views without doing the below in every single route in (controller.js):
index = (req, res) => {
res.render("index", {
role: req.oidc.user['https://localhost:3000.com/roles'],
});
};
As you've said, your code is trying to read a value from a variable that might be undefined.
You can either use a condition to check wether req.oidc.user exists before reading from it or have optional chaining in order to "short-circuit" the expression to undefined without causing an error.
This is your code with optional chaining:
app.use((req, res, next) => {
res.locals.role = req.oidc.user?.['https://localhost:3000.com/roles'] ?? "null";
});
Side note, I suggest not using "null" as your default value. Maybe use an empty string ("") which is also a falsy value.