reactjs - 为子项提供属性时如何将正确的类型分配给 React.cloneElement？

Question

我正在使用 React 和 Typescript。我有一个充当包装器的 react 组件，我希望将它的属性复制到它的子组件。我正在遵循 React 的克隆元素使用指南:https://facebook.github.io/react/blog/2015/03/03/react-v0.13-rc2.html#react.cloneelement .但是当使用 React.cloneElement 时，我从 Typescript 得到以下错误:

Argument of type 'ReactChild' is not assignable to parameter of type 'ReactElement<any>'.at line 27 col 39
  Type 'string' is not assignable to type 'ReactElement<any>'.

如何将正确的类型分配给 react.cloneElement？

这是一个复制上述错误的示例:

import * as React from 'react';

interface AnimationProperties {
    width: number;
    height: number;
}

/**
 * the svg html element which serves as a wrapper for the entire animation
 */
export class Animation extends React.Component<AnimationProperties, undefined>{

    /**
     * render all children with properties from parent
     *
     * @return {React.ReactNode} react children
     */
    renderChildren(): React.ReactNode {
        return React.Children.map(this.props.children, (child) => {
            return React.cloneElement(child, { // <-- line that is causing error
                width: this.props.width,
                height: this.props.height
            });
        });
    }

    /**
     * render method for react component
     */
    render() {
        return React.createElement('svg', {
            width: this.props.width,
            height: this.props.height
        }, this.renderChildren());
    }
}

Answer 1

问题是 definition for ReactChild这是:

type ReactText = string | number;
type ReactChild = ReactElement<any> | ReactText;

如果您确定 child 始终是 ReactElement 则强制转换它:

return React.cloneElement(child as React.ReactElement<any>, {
    width: this.props.width,
    height: this.props.height
});

否则使用isValidElement type guard :

if (React.isValidElement(child)) {
    return React.cloneElement(child, {
        width: this.props.width,
        height: this.props.height
    });
}

(我没用过，但是根据定义文件是有的)