** 嘗試運行此代碼時出現錯誤“TypeError：searchField.toLowerCase 不是函數”，而代碼正在編譯成功**import React, { Component } from 'react';import CardList from '../Components/CardList';import SearchBox from '../Components/SearchBox';//import { robots } from './robot';import './App.css';import Scroll from '../Components/Scroll';import ErrorBoundry from '../Components/ErrorBoundry';import { connect } from 'react-redux';import { searchChange } from '../actions'         const mapStateToProps = state => {    return {searchField:state.searchField} }  const mapDispatchToProps = (dispatch) =>{    return {        searchField:(event) => dispatch(searchChange(event.target.value))    } }  class App extends Component {    constructor(){        super()        this.state = {            robots:[]        }       }          componentDidMount() {        fetch('https://jsonplaceholder.typicode.com/users').then(respond =>{            return respond.json()        }).then(users =>{             this.setState({robots:users})        })    }        render(){        const { searchField, onSearchChange } = this.props;        const filterRobots = this.state.robots.filter(robots =>{            //trying to search robot with either upper case or lower case            return robots.name.toLowerCase().includes(searchField.toLowerCase())        });         return(            <div className="tc">            <h1 className="head"> Robo Friend App</h1>            <div>            <SearchBox searchChange={onSearchChange}/>            </div>             <Scroll>            <ErrorBoundry>            <CardList robots={filterRobots} />            </ErrorBoundry>            </Scroll>            </div>            )    }     }  export default connect(mapStateToProps, mapDispatchToProps)(App);