README.md

useEffectOnce & useLayoutEffectOnce

What is it?

• Expansions of useEffect and useLayoutEffect, but will conditional execution
• If no condition (3rd argument) is passed, then it'll only run once, on mount
• If a condition is passed, then it'll run until that condition is true

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Prereuisites

• React

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API

useEffectOnce

export const useEffectOnce = (effect: EffectCallback, deps?: DependencyList, condition?: boolean) => {

useLayoutEffectOnce

export const useLayoutEffectOnce = (effect: EffectCallback, deps?: DependencyList, condition?: boolean) => {

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How to use it?

const Component = ({ data, isFetched }: { data?: Record<string, string>; isFetched?: boolean }) => {
  useEffectOnce(
    () => {
      // This will get executed once the 3rd argument is `true`, and then never again
      // if no 3rd argument is passed, then it'll only run once, on mount

      return () => {
        // This will still run on unmount
      };
    },
    [data, isFetched],
    !!data && isFetched,
  );

  return <>{...JSX}</>;
};

---

.eslintrc.js

Given that you're utilising the react-hooks/exhaustive-deps eslint rule.

In order to get the eslint validation to work, we need to add the following to the .eslintrc.js file:

module.exports = {
  ...
  rules: {
    ...
    'react-hooks/exhaustive-deps': [
      1,
      {
        additionalHooks: '(useEffectOnce|useLayoutEffectOnce)', // I'm the important part 😂❤️
      },
    ],
    ...
  },
};