Controlled Inputs

In React, form inputs can be "controlled" by React state. This means React becomes the single source of truth for the input's value.

What is a Controlled Input?

A controlled input is one where React controls the value through state:

The Controlled Input Pattern

The key to controlled inputs is the two-way binding between state and the input:

Why Use Controlled Inputs?

Controlled inputs give you complete control over the data:

Exercise: Create a Controlled Input

Exercise: Input with Transformation

Exercise: Number-Only Input

Different Input Types

React controls different input types in similar ways:

Key Takeaways

1. Controlled inputs - React state is the single source of truth
2. value + onChange - The two props that make inputs controlled
3. Immediate access - Always know the current value
4. Transform on change - Modify values before storing
5. Validation - Check values as the user types