React 104

Controlled components

• The state of form elements in an HTML/JavaScript project is tracked by <1>.
• A controlled component in React is really just a regular <2> that you are already familiar with.
• But the term refers to a component that has a form element whose <3> is tracked by <4>.
• The value of an <input />, for example, in a controlled component is set by the <5> part of the useState hook.
• If an <input /> does not have a <6> attribute, its state is controlled by HTML.
• Changes in state cause a React component to <7>.
• When component goes from controlled to uncontrolled, React will throw a <8>.
• The onChange event listener listens to every <9>.
• The <input /> of a controlled component will always have the <10> event listener as one of its attributes.
• A controlled component must implement the <11> as well as have attributes for value and onChange on the <input /> element.

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Key terms and phrases

1. component
2. HTML
3. keypress
4. noun
5. onChange
6. re-render
7. React
8. state
9. useState hook
10. value
11. warning