我在是新阵营的js传数据从小孩到在母体阵营节目类型错误
我试图通过从子到父值和同时示出通过地图部件那里示出了在所述发送/触发一个错误功能
render(){
var choices =['krass', 'Einfach', 'Dazu', 'Dafur'];
const listitem = choices.map(function(name, index){
this.increaseCount} key={index} option={name} /> ;
});
return (
<div className="col-md-12 row">
{listitem}
div>
);
}
下面错误信息显示
react-dom.development.js:10289 The above error occurred in the component:
in Choices (created by App)
in div (created by App)
in div (created by App)
in App
Consider adding an error boundary to your tree to customize error handling behavior.
boundaries.
logCapturedError @ react-dom.development.js:10289
captureError @ react-dom.development.js:11082
renderRoot @ react-dom.development.js:10933
performWorkOnRoot @ react-dom.development.js:11556
performWork @ react-dom.development.js:11509
requestWork @ react-dom.development.js:11420
scheduleWorkImpl @ react-dom.development.js:11274
scheduleWork @ react-dom.development.js:11231
scheduleTopLevelUpdate @ react-dom.development.js:11735
updateContainer @ react-dom.development.js:11773
(anonymous) @ react-dom.development.js:15900
unbatchedUpdates @ react-dom.development.js:11644
renderSubtreeIntoContainer @ react-dom.development.js:15899
render @ react-dom.development.js:15964
(anonymous) @ Inline Babel script:141
n @ babel.min.js:12
r @ babel.min.js:12
o @ babel.min.js:12
u @ babel.min.js:12
E @ babel.min.js:1
codepen链路是https://codepen.io/jahid93/pen/VypwjO
2 回答
你没有从.map返回任何东西。
它改成这样：
const listitem = choices.map((name, index) => {
return(this.increaseCount} key={index} option={name} />);
注意，我改变的map匿名函数到arrow function处理的this上下文中词汇的方式。
从您的代码笔链路上运行代码：
class Header extends React.Component {
render() {
return (
<div className="col-md-8 col-sm-8 col-xs-8">
<p className="title-p">
<span className="red-text">Bspan>
<span className="black-text">ulowsspan>{" "}
<span className="green-text">Wortshatztestspan>
p>
div>
);
}
}
class Hicon extends React.Component {
render() {
return (
<div className="col-md-4 col-sm-4 col-xs-4 icon-image-div">
<img className="icon-image" src="src/img/WT_icon5.png" alt="icon" />
div>
);
}
}
class Question extends React.Component {
render() {
return (
<div className="col-md-12 text-center">
<h3 className="question-type">Welche beiden Worter passen gut zu:h3>
<h1 className="question">Gegensatzh1>
div>
);
}
}
class Instruction extends React.Component {
render() {
return (
<div className="col-md-12">
<h4 className="attention-text">
Wählen Sie Ihre zwei. [attention German Umlaut = auml]
h4>
div>
);
}
}
class Choice extends React.Component {
constructor(props) {
super(props);
this.state = { isToggleOn: true, selectCount: 0 };
this.handleClick = this.handleClick.bind(this);
}
handleClick() {
this.setState(prevState => ({
isToggleOn: !prevState.isToggleOn
}));
console.log(this.state.isToggleOn);
this.props.onIncreaseCount();
}
render() {
let bgColor = this.state.isToggleOn ? "white" : "green";
return (
<div className="col-md-6 text-center btn-div">
<a
style={{ backgroundColor: bgColor }}
onClick={this.handleClick}
type="button"
className="btn"
href="#"
>
{this.props.option}
a>
div>
);
}
}
class Choices extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0,
choices: [
{ option: "Krass" },
{ option: "Einfach" },
{ option: "Dazu" },
{ option: "Dafur" }
]
};
this.increaseCount = this.increaseCount.bind(this);
}
increaseCount() {
this.setState(prevState => ({
count: prevState.count + 1
}));
if (this.state.count == 2) {
console.log("kam sarse");
}
}
render() {
var choices = ["krass", "Einfach", "Dazu", "Dafur"];
const listitem = choices.map((name, index) => {
return(<Choice onIncreaseCount={this.increaseCount} key={index} option={name} />);
});
return (
<div className="col-md-12 row">
<Choice onIncreaseCount={this.increaseCount} option="Krass" />
{listitem}
div>
);
}
}
class App extends React.Component {
render() {
return (
<div className="container">
<div className="row header">
<Header />
<Hicon />
div>
<div className="row question-div">
<Question />
div>
<div className="row instruction-div">
<Instruction />
div>
<div className="row choice-div">
<Choices />
div>
div>
);
}
}
ReactDOM.render(<App />, document.getElementById("root"));.header{
border-bottom: 5px solid black;
margin-bottom: 20px;
}
.title-p{
padding-bottom: 0px !important;
margin-bottom: -10px;
}
.red-text{
font-size: 60px;
font-weight: bold;
color: red;
}
.black-text{
font-weight: bold;
font-size: 25px;
}
.green-text{
font-size: 35px;
font-weight: 600;
color: green;
}
.icon-image{
height: 50px;
float: right;
}
.icon-image-div{
padding-top: 25px;
}
.question-div{
background-color: aliceblue;
min-height: 20%;
}
.instruction-div{
background-color: goldenrod;
margin-top: 20px;
}
.choice-div{
margin-top: 30px;
}
.zero-padding{
padding: 0 !important;
margin: 0 !important;
}
.btn-div{
margin-top: 15px;
margin-bottom: 15px;
}
.btn{
width: 80%;
font-weight: bold;
font-size: 30px;
color: black;
}
.btn:hover{
background-color: aquamarine;
}
.btn:focus{
box-shadow: 0 0 0 0 !important;
/*background-color: green;*/
/*color: white;*/
}<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js">script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js">script>
<div id="root">div>这家伙很懒，还没有设置简介
