Tripple-A

import { useReducer } from "react";

const initialState = {
  age: 0,
  height: 0,
  hobby: "None",
};

const reducer = (state, action) => {
  switch (action.type) {

Tripple-A

  <button onClick={() => dispatch({ type: "startBabyStage" })}>Baby</button>
  <button onClick={() => dispatch({ type: "startTeenStage" })}>
    Teenager
  </button>
  <button onClick={() => dispatch({ type: "startAdultStage" })}>
    Adult
  </button>

Tripple-A

const [state, dispatch] = useReducer(reducer, initialState);
const { age, hobby, height } = state;

Tripple-A

const initialState = {
  age: 0,
  height: 0,
  hobby: "None",
};

const reducer = (state, action) => {
  switch (action.type) {
    case "startBabyStage":
      return { ...state, age: 1, height: 29, hobby: "Biting" };

Tripple-A

import { useState } from "react";

function App() {
  const [age, setAge] = useState(0);
  const [height, setHeight] = useState(0);
  const [hobby, setHobby] = useState("None");

  const startBabyStage = () => {
    setAge(1);
    setHeight(29);

Tripple-A

const reducer = (state, action) => {
  if (action.type == 'DOUBLE') {
      return state * 2 ;
  } else if(action.type == 'TRIPLE') {
      return state * 3;
  } else {
      return state;
  }
}