Question

我已将我的项目更新为React 16.3.1，现在我收到此错误：

Uncaught Error: Element ref was specified as a string (map) but no owner was set. You may have multiple copies of React loaded. (details: https://fb(dot)me/react-refs-must-have-owner).
    at invariant (invariant.js:42)
    at coerceRef (react-dom.development.js:6736)
    at createChild (react-dom.development.js:6977)
    at reconcileChildrenArray (react-dom.development.js:7282)
    at reconcileChildFibers (react-dom.development.js:7651)
    at reconcileChildrenAtExpirationTime (react-dom.development.js:7756)
    at reconcileChildren (react-dom.development.js:7747)
    at updateHostComponent (react-dom.development.js:7998)
    at beginWork (react-dom.development.js:8229)
    at performUnitOfWork (react-dom.development.js:10224)
    at workLoop (react-dom.development.js:10288)
    at HTMLUnknownElement.callCallback (react-dom.development.js:542)
    at Object.invokeGuardedCallbackDev (react-dom.development.js:581)
    at invokeGuardedCallback (react-dom.development.js:438)
    at renderRoot (react-dom.development.js:10366)
    at performWorkOnRoot (react-dom.development.js:11014)
    at performWork (react-dom.development.js:10967)
    at requestWork (react-dom.development.js:10878)
    at scheduleWorkImpl (react-dom.development.js:10732)
    at scheduleWork (react-dom.development.js:10689)
    at Object.enqueueSetState (react-dom.development.js:6212)
    at Wrapper.../node_modules/react/cjs/react.development.js.Component.setState (react.development.js:242)
    at Wrapper.onLoad (GoogleApiComponent.js:194)
    at ScriptCache.js:39

我是一个新手，所以我不确定我应该找到什么来发现错误。

PS。我已经排除了多份副本选项，因为当我运行npm ls react时，我得到了：

└── react@16.3.1

Answer 1

根据对版本16.3更改的响应文档，不建议使用旧字符串ref api，现在您应按以下方式使用ref回调api

class MyComponent extends React.Component {
  constructor(props) {
    super(props);

    this.inputRef = React.createRef();
  }

  render() {
    return <input type="text" ref={this.inputRef} />;
  }

  componentDidMount() {
    this.inputRef.current.focus();
  }
}

元素引用被指定为字符串（映射），但未设置所有者

1 个答案: