如何将状态数组转移到道具

Question

So I have 2 React files, an App.js and a category.js. When I transfer my array to category.js, it shows a huge blob of text instead of splitting it into different array buttons. I tried searching but I don't understand how to do it. Can someone explain it?

here is the class App

class App extends React.Component {
Object.keys(data.categories).forEach((category,index) => {
    arr.push(data.categories[index].name);
})

render() {
return (
<div>
    <Categories 
      categoryName = { this.state.categoryName }
    />
</div>

and here is the categories using props

const Categories = props => (
<div>
    <br /> 
    { props.categoryName && <button> { props.categoryName } </button>}
</div>
);

Answer 1

You need to map over your categoryName array

const Categories = props => (
   <div>
      <br /> 
      { props.categoryName &&
        props.categoryName.map(name => <button>{name}</button>)}
   </div>
   );

Answer 2

Assuming your categories are an array of objects in your component state, map over the state categories and return a Category component with each iteration of the array.

 function Category({ categoryName }) { return (<button>{categoryName}</button>); } class App extends React.Component { constructor(props) { super(props); this.state = { categories: [ { categoryName: 'Bob', type: 'string' }, { categoryName: 'Trevor', type: 'number' }] }; } render() { return ( <div> {this.state.categories.map(category => { return <Category categoryName={category.categoryName} /> })} </div> ) } } ReactDOM.render( <App />, document.getElementById('container') ); 

 <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="container"></div>