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---title: Custom useAtom hooksnav: 5.03---

This page shows the ways of creating different utility functions. Utility functions save your time on coding, and you can preserve your base atom for other usage.
## utils
### useSelectAtom
```tsimport { useAtomValue } from 'jotai'import { selectAtom } from 'jotai/utils'
/* if an atom is created here, please use `useMemo(() => atom(initValue), [initValue])` instead. */export function useSelectAtom(anAtom, keyFn) {    return useAtomValue(selectAtom(anAtom, keyFn))}
// how to use ituseSelectAtom(    useMemo(() => atom(initValue), [initValue]),    useCallBack((state) => state.prop, []))```
Please note that in this case `keyFn` must be stable, either define outside render or warp with `useCallback`.
### useFreezeAtom
```tsimport { useAtom } from 'jotai'import { freezeAtom } from 'jotai/utils'
export function useFreezeAtom(anAtom) {    return useAtom(freezeAtom(anAtom))}```
### useSplitAtom
```tsimport { useAtom } from 'jotai'import { splitAtom } from 'jotai/utils'
export function useSplitAtom(anAtom) {    return useAtom(splitAtom(anAtom))}```
## integrations
### useFocusAtom
```tsimport { useAtom } from 'jotai'import { focusAtom } from 'jotai/optics'
/* if an atom is created here, please use `useMemo(() => atom(initValue), [initValue])` instead. */export function useFocusAtom(anAtom, keyFn) {    return useAtom(focusAtom(anAtom, keyFn))}
// how to use ituseFocusAtom(anAtom) {    useMemo(() => atom(initValue), [initValue]),    useCallBack((optic) => optic.prop('key'), [])}```
### CodeSandbox
<CodeSandbox id="y5wef8" />Please note that in this case `keyFn` must be stable, either define outside render or warp with `useCallback`.