所以我有一个React组件，SearchBooks接收来自主books状态的数组App.js以及一个函数onUpdateBooksState，也来自{ {1}}。
一切正常但我收到的警告说没有被使用，但它们都是。
为什么我会收到这些警告？如何纠正潜在问题？
App.js
SearchBooks.js编译器警告：
import React, { Component } from 'react'
import * as BooksAPI from './utils/BooksAPI'
import Book from './Book';
export default class SearchBooks extends Component {
state = {
query: '',
results: []
}
updateQuery(query) {
this.setState(() => ({
results: [],
query: query
}))
this.bookSearch(query)
}
bookSearch(e) {
if (e.length > 0)
BooksAPI.search(e)
.then(searchResults => this.setState(currentState => ({
results: this.updateExistingShelves(searchResults)
})));
}
updateExistingShelves(searchResults) {
if(searchResults.error !== "empty query") {
const myBooks = this.props.books // books used here
const addToState = searchResults.filter((result) => myBooks.find(b => {
if(b.id === result.id)
result.shelf = b.shelf
return result
}))
myBooks.concat(addToState)
return searchResults
}
}
render() {
const { query, results } = this.state
const { onUpdateShelf, books, onUpdateBooksState } = this.props
return(
<div className="search-books">
<div className="search-books-bar">
<a className="close-search" >Close</a>
<div className="search-books-input-wrapper">
<input
type="text"
placeholder="Search by title, author or subject"
value={query}
onChange={(event) => this.updateQuery(event.target.value)}
/>
</div>
</div>
<div className="search-books-results">
<ol className="books-grid">
<li>
{ results ? (
results.map((book) => (
<Book
key={book.id}
book={book}
updateShelf={onUpdateShelf} // onUpdateShelf used here
/>
))
) : (
<h4>No results for, "{query}"</h4>
)}
</li>
</ol>
</div>
</div>
)
}
}
Chrome警告：
./src/SearchBooks.js
Line 45: 'books' is assigned a value but never used no-unused-vars
Line 45: 'onUpdateBooksState' is assigned a value but never used no-unused-vars答案 0 :(得分：2)
它是一个EsLint警告，可以防止您声明未使用的变量。
在此行中，您声明（不使用）变量
const { onUpdateShelf, books, onUpdateBooksState } = this.props
变量books和onUpdateBooksState不会在代码中的任何位置使用。
摆脱它们并将线路改为
const { onUpdateShelf } = this.props