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metamask-extension/ui/app/hooks/useEqualityCheck.js
Mark Stacey 14d85b1332
Make JSDoc formatting more consistent (#9796)
A few inconsistencies in JSDoc formatting have been fixed throughout
the project. Many issues remain; these were just the few things that
were easy to fix with a regular expression.

The changes include:

* Using lower-case for primitive types, but capitalizing non-primitive
 types
* Separating the parameter identifier and the description with a dash
* Omitting a dash between the return type and the return description
* Ensuring the parameter type is first and the identifier is second (in
 a few places it was backwards)
* Using square brackets to denote when a parameter is optional, rather
 than putting "(optional)" in the parameter description
* Including a type and identifier with every parameter
* Fixing inconsistent spacing, except where it's used for alignment
* Remove incorrectly formatted `@deprecated` tags that reference non-
 existent properties
* Remove lone comment block without accompanying function

Additionally, one parameter was renamed for clarity.
2020-11-10 14:00:41 -03:30

28 lines
937 B
JavaScript

import { useState, useLayoutEffect } from 'react'
import { isEqual } from 'lodash'
/**
* Given a value and a function to determine equality, return a
* referentially equal value if the equality function returns true.
* This hook is helpful in avoiding re-renders and effects running
* based on an object or value that always changes references but
* infrequently changes it's value. By default, uses isEqual from
* lodash. This is typically only useful with objects and arrays.
*
* @param {T} value - any value to check equality of
* @param {(T, T) => boolean} equalityFn - A function to determine equality
* @returns {T}
*/
export function useEqualityCheck(value, equalityFn = isEqual) {
const [computedValue, setComputedValue] = useState(value)
useLayoutEffect(() => {
if (!equalityFn(value, computedValue)) {
setComputedValue(value)
}
}, [value, equalityFn, computedValue])
return computedValue
}