Guoba UtilsusePrevious
@guoba-ai/hook / usePrevious
Function: usePrevious()
function usePrevious<T>(value): T | undefined;Defined in: usePrevious.ts:24
Track the previous value of a variable across renders.
Parameters
value
T
The current value to track
Returns
T | undefined
The value from the previous render, or undefined on the first render
Example
const [count, setCount] = useState(0)
const prevCount = usePrevious(count)
// After setCount(1): prevCount === 0
// After setCount(2): prevCount === 1
const prevName = usePrevious(name)
// First render: prevName === undefined
const prevUser = usePrevious(user)
// Object values are returned by their previous referenceWarning
Returns undefined on the first render because there is no previous value yet.