In React's useState
hook, lazy initialization refers to initializing the state with a function instead of a direct value.
Lazy initialization is useful when the initial state value requires some computation or relies on the current state or props. By passing a function as the initial value, React calls that function only during the initial rendering, ensuring the correct value is computed.
Here's an example:
import React, { useState } from 'react';
function Counter() {
const [count, setCount] = useState(() => {
// Some complex computation or logic
return 0;
});
// ...
}
In the above example, the useState
hook is used to create a state variable count
, initialized with the result of the function () => 0
. The function will be called only during the initial rendering.
Using lazy initialization can improve performance and prevent unnecessary computations if the initial state value is costly to compute.