# What is the state of an app?

# Understanding with a concrete example

The state of an application is like a snapshot of it at a specific time.

For example, imagine this TodoMVC example.

When you launch the application, it's in an initial state. Applied to the context of TodoMVC, the initial state is:

• empty list of todos
• input is empty

When you start typing stuff inside the text input, the application state changes:

• the todo list stays empty
• the input is now filled with some typed value

When you press enter, a todo item appears in the list. The new state is now:

• todo list has 1 item
• the input has been cleared, so it's empty again

# Representation with code

const t1State = { firstName: "Marvin", lastName: "Frachet" };

const t2State = transform(t1State, { lastName: "Thomas" });
// t2State is now { firstName: "Marvin", lastName: "Thomas" }

Every frontend framework uses its own internal way to transform and manage state.