isabella232 / use-memo-value

Reuse the previous version of a value unless it has changed

useMemoValue()

Reuse the previous version of a value unless it has changed

Install

npm install --save-dev use-memo-value

Usage

If you don't know all the members of an object, you may want to use a "shallow compare" to memoize the value so you can rely on React's referential equality (such as in useEffect(..., deps)).

import useMemoValue from "use-memo-value"

function MyComponent(props) {
  let rawParams = getCurrentUrlQueryParams() // we don't know the shape of this object
  let memoizedParams = useMemoValue(rawParams)

  useEffect(() => {
    search(memoizedParams)
  }, [memoizedParams])

  // ...
}

Note: If you know the shape of your object, you are likely better off not using this library.

If you need to customize how the values are compared, you can pass a comparator as a second argument:

let memoizedValue = useMemoValue(rawValue, (nextValue, previousValue) => {
  return Object.is(a, b) // or whatever
})

The comparator will not be called until there's a new value.