EduVencovsky

import { AsyncStorage } from 'react-native' // change this to @react-native-community/async-storage when this issue is solved https://github.com/react-native-community/react-native-async-storage/issues/14

export default Storage = {
    async getItem(itemKey) {
        let result = {
            key: itemKey,
            value: null,
            error: null,
        }

EduVencovsky

import { useReducer } from 'react'

function arrayReducer(array, action) {
    switch (action.type) {
        case 'push':
            return [...array, action.value]
        case 'pushAll':
            return [...array, ...action.value]
        case 'deleteByIndex':
            let deleteByIndex = array.filter((x, i) => i != action.index)

EduVencovsky

.li {
  max-height: 0px;
  transition: max-height 0.35s ease-out;
}
.ul {
  overflow: hidden;
}

.ul.opened .li {
  max-height: 50px;

EduVencovsky

// https://overreacted.io/making-setinterval-declarative-with-react-hooks/
import { useEffect, useRef } from 'react'

function useInterval(callback, delay) {
    const savedCallback = useRef()

    // Remember the latest callback.
    useEffect(() => {
        savedCallback.current = callback
    }, [callback])

EduVencovsky

import { useEffect, useRef, useState } from 'react'

// The callback should setState so it will re trigger the timeout
function useTimeout(callback, delay) {
    const savedCallback = useRef()
    const [callBackCleanUp, setCallBackCleanUp] = useState(null)
    // Remember the latest callback.
    useEffect(() => {
        savedCallback.current = callback
    }, [callback])

EduVencovsky

import { useState, useEffect } from 'react'
import Realm from '../database/migrations'

function reducer(action, { realm, name, queryObjects }) {
    switch (action.type) {
    case 'create':
        return new Promise((resolve, reject) => {
            try {
                realm.write(() => {
                    resolve(realm.create(name, action.data))

EduVencovsky

import { useState } from 'react'

export default function useToggle(defaultValue){
    const [state, setState] = useState(defaultValue)
    
    const toggle = (value = null) => {
        if(value == null) 
            setState(!state)
        else 
            setState(!!value)

EduVencovsky

<button id="open">open</button>
<div class="box scale">
  <h1>
  hey
  </h1>
</div>

EduVencovsky

import { useState, useEffect, useRef } from 'react'

export const useNavigationFocusChanged = (navigation, event) => {
    const [focus, setFocus] = useState(false)
    const listener = useRef(null)
    useEffect(() => {
        const changeFocus = () => {
            setFocus(prev => !prev)
        }
        listener.current = navigation.addListener(event, changeFocus)

EduVencovsky

import React, { useEffect, useState } from 'react'
import PropTypes from 'prop-types'
import { Animated, Easing } from 'react-native'

const RotateView = ({ rotate, degree, initialDegree, duration, children, ...otherProps }) => {

    const [rotateValue] = useState(new Animated.Value(0))

    useEffect(() => {
        const toValue = rotate ? 1 : 0