React Mount Effects

React allows useEffect(() => {callback()}, []) to run the callback only on first mount, thus useEffect(() => callback, []) only runs on unmounting. However, eslint often complains about this. This library manually suppresses those warnings and exports the hooks for convenience sake.

The hooks are not exported as default, so you can import in one of the following ways:

//ES6
import { useMountEffect, useUnmountEffect, useDelayedEffect } from '@ptolemy2002/react-mount-effects';
//CommonJS
const { useMountEffect, useUnmountEffect, useDelayedEffect } = require('@ptolemy2002/react-mount-effects');

The example for this library purposefully does not run in strict mode, as doing so allows more clear demonstration of exactly when each hook runs (console logs are run only once and there aren't any extraneous mounts/unmounts).

Hooks

The following hooks are available in the library:

useMountEffect

Description

Runs the callback only on first mount. The return value of the callback is ignored.

Parameters

• callback (Function): The callback to run on first mount.

Returns

None

useUnmountEffect

Description

Runs the callback only on unmount. The return value of the callback is ignored.

Parameters

• callback (Function): The callback to run on unmount.

Returns

None

useDelayedEffect

Description

Runs the callback only after it has been triggered delay + 1 times (since the first is on mount and does not represent a state change). The return value of the callback is ignored.

Parameters

• callback (Function): The callback to run after the delay. The first parameter is the number of times the effect has been triggered since either initialization or last reset, and the second argument is a function that allows you to reset the counter.
• deps (Array): An array of dependencies to listen to. This works exactly like the useEffect hook's dependencies.
• delay (Number): The number of times the dependencies must change before the callback is run. Default is 0, meaning the callback is run on any change, but not on mount.

Returns

None

Meta

This is a React Library Created by Ptolemy2002's cra-template-react-library template in combination with create-react-app. It contains methods of building and publishing your library to npm. For now, the library makes use of React 18 and does not use TypeScript.

Peer Dependencies

These should be installed in order to use the library, as npm does not automatically add peer dependencies to your project.

• @types/react: ^18.3.3
• @types/react-dom: ^18.3.0
• react: ^18.3.1
• react-dom: ^18.3.1

Commands

The following commands exist in the project:

• npm run uninstall - Uninstalls all dependencies for the library
• npm run reinstall - Uninstalls and then Reinstalls all dependencies for the library
• npm run example-uninstall - Uninstalls all dependencies for the example app
• npm run example-install - Installs all dependencies for the example app
• npm run example-reinstall - Uninstalls and then Reinstalls all dependencies for the example app
• npm run example-start - Starts the example app after building the library
• npm run build - Builds the library
• npm run release - Publishes the library to npm without changing the version
• npm run release-patch - Publishes the library to npm with a patch version bump
• npm run release-minor - Publishes the library to npm with a minor version bump
• npm run release-major - Publishes the library to npm with a major version bump