use-memo-one v1.1.3
useMemoOne
useMemo
and useCallback
with a stable cache (semantic guarantee)
Background
useMemo
and useCallback
cache the most recent result. However, this cache can be destroyed by React
when it wants to:
You may rely on useMemo as a performance optimization, not as a semantic guarantee. In the future, React may choose to “forget” some previously memoized values and recalculate them on next render, e.g. to free memory for offscreen components. Write your code so that it still works without useMemo — and then add it to optimize performance. - React docs
useMemoOne
and useCallbackOne
are concurrent mode
safe alternatives to useMemo
and useCallback
that do provide semantic guarantee. What this means is that you will always get the same reference for a memoized value so long as there is no input change.
Using useMemoOne
and useCallbackOne
will consume more memory than useMemo
and useCallback
in order to provide a stable cache. React
can release the cache of useMemo
and useCallback
, but useMemoOne
will not release the cache until it is garbage collected.
Install
# npm
npm install use-memo-one --save
# yarn
yarn add use-memo-one
Usage
import { useMemoOne, useCallbackOne } from 'use-memo-one';
function App(props) {
const { name, age } = props;
const value = useMemoOne(() => ({ hello: name }), [name]);
const getAge = useCallbackOne(() => age, [age]);
// ...
}
Aliased imports
You can use this import
style drop in replacement for useMemo
and useCallback
This style also plays very well with eslint-plugin-react-hooks
.
import { useMemo, useCallback } from 'use-memo-one';
⚠️ The aliased exports useMemo
and useCallback
will only work if you use only use-memo-one
and will clash if you also use useMemo
or useCallback
from react
import { useMemo, useCallback } from 'react';
// ❌ naming clash
import { useMemo, useCallback } from 'use-memo-one';
API
See useMemo
and useCallback
Linting
useMemo
and useCallback
have fantastic linting rules with auto fixing in the eslint-plugin-react-hooks
package. In order to take advantage of these with useMemoOne
and useCallbackOne
, structure your import like this:
import { useMemo, useCallback } from 'use-memo-one';
// Or your can alias it yourself
import {
useMemoOne as useMemo,
useCallbackOne as useCallback,
} from 'use-memo-one';
function App() {
const [isActive] = useState(false);
const onClick = useCallback(() => {
console.log('isActive', isActive);
// the input array will now be correctly checked by eslint-plugin-react-hooks
}, [isActive]);
}
eslint
rules
Here are some eslint
rules you are welcome to use
module.exports = {
rules: {
// ...other rules
'no-restricted-imports': [
'error',
{
// If you want to force an application to always use useMemoOne
paths: [
{
name: 'react',
importNames: ['useMemo', 'useCallback'],
message:
'`useMemo` and `useCallback` are subject to cache busting. Please use `useMemoOne`',
},
// If you want to force use of the aliased imports from useMemoOne
{
name: 'use-memo-one',
importNames: ['useMemoOne', 'useCallbackOne'],
message:
'use-memo-one exports `useMemo` and `useCallback` which work nicer with `eslint-plugin-react-hooks`',
},
],
},
],
},
};