Counter.jsx

Counter.jsx

import React, { useReducer } from 'react'
import styled from '@emotion/styled'
import { sleep } from '../../utils/schedule.js'

const initialState = { count: 7n }

function reducer(state = initialState, action) {
    if (action.type === 'setCount') {
        return {
            ...state,
            count: action.payload
        }
    }
    return state
}

const Container = styled.div`
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 75vh;

  & input {
    max-width: 60%;
    border-width: 0 0 .5px 0;
    outline: none;
    font-size: 30px;
    text-align: center;
  }

  & button {
    border-radius: 4px;
    font-size: 14px;
    margin: 11px 4px;
    padding: 0 16px;
    border: 0;
    line-height: 27px;
    height: 36px;
    min-width: 80px;
    text-align: center;
    outline: none;
    user-select: none;
    background-color: #f8f9fa;
    transition: color 0.3s;
  }

  & button:hover {
    box-shadow: 0 1px 1px rgba(0, 0, 0, .1);
    border: 1px solid #dadce0;
    color: #202124;
  }

  & button:active {
    color: rgba(0, 0, 0, 0.3)
  }

  & button:disabled {
    color: rgba(0, 0, 0, 0.3)
  }
`

function convertToBigInt(value, def) {
    try {
        return BigInt(value)
    } catch (err) {
        alert(err.message)
        return def
    }
}

export default function Counter(props) {

    const [state, dispatch] = useReducer(reducer, initialState);
    const count = state.count

    const [plus1sButtonDisabled, setPlus1sButtonDisabled] = React.useState(false)

    function onInputChange(ev) {
        dispatch({
            type: 'setCount',
            payload: convertToBigInt(ev.target.value, count)
        })
    }

    function onClickMinus() {
        dispatch({
            type: 'setCount',
            payload: count - 1n
        })
    }

    async function onClickPlus1s() {
        setPlus1sButtonDisabled(true)
        await sleep(1000)
        dispatch({
            type: 'setCount',
            payload: count + 1n
        })
        setPlus1sButtonDisabled(false)
    }

    return (
        <Container>
            <input type="text" value={String(count)} onChange={onInputChange}/>
            <div>
                <button onClick={onClickMinus}>-</button>
                <button onClick={onClickPlus1s} disabled={plus1sButtonDisabled}>+1s</button>
            </div>
        </Container>
    )
}