NextJS动态导入问题

Question

我在dynamicimport from方面遇到了一个非常奇怪的问题NextJS。

我正在导入一个像这样的组件：

const Spinner = dynamic(() => import('components/ui/Spinner').then(mod => mod.Spinner))

并且Spinner.tsx是

import {useEffect, useState} from 'react'
import PulseLoader from 'react-spinners/PulseLoader'

import {FadeHOC} from '.'
import theme from 'utils/theme'


interface Props {
  inline?: boolean
}

const TIMEOUT = 1000

export const Spinner = ({inline}: Props) => {

  const [show, setShow] = useState(false)

  useEffect(() => {
    
    const timeout = setTimeout(
      () => setShow(true),
      TIMEOUT
    )
    
    return () => clearTimeout(timeout)
  }, [])

  return (
    show
      ? <FadeHOC>
          <PulseLoader size={10} margin={3} color={theme.color} css={inline ? 'margin-left: 14px;' : 'display: block; text-align: center; margin: 100px auto;'} />
        </FadeHOC>
      : null
  )
}

在dynamic进口声明中我收到TypeScript投诉：

Argument of type '() => Promise<(({ inline }: Props) => JSX.Element) | ComponentClass<never, any> | FunctionComponent<never> | { default: ComponentType<never>; }>' is not assignable to parameter of type 'DynamicOptions<{}> | Loader<{}>'.
  Type '() => Promise<(({ inline }: Props) => JSX.Element) | ComponentClass<never, any> | FunctionComponent<never> | { default: ComponentType<never>; }>' is not assignable to type '() => LoaderComponent<{}>'.
    Type 'Promise<(({ inline }: Props) => Element) | ComponentClass<never, any> | FunctionComponent<never> | { default: ComponentType<never>; }>' is not assignable to type 'LoaderComponent<{}>'.
      Type '(({ inline }: Props) => Element) | ComponentClass<never, any> | FunctionComponent<never> | { default: ComponentType<never>; }' is not assignable to type 'ComponentType<{}> | { default: ComponentType<{}>; }'.
        Type '({ inline }: Props) => JSX.Element' is not assignable to type 'ComponentType<{}> | { default: ComponentType<{}>; }'.
          Type '({ inline }: Props) => JSX.Element' is not assignable to type 'FunctionComponent<{}>'.
            Types of parameters '__0' and 'props' are incompatible.
              Type '{ children?: ReactNode; }' has no properties in common with type 'Props'.ts(2345)

我不明白投诉的内容是什么，非常感谢您的帮助！

Answer 1

dynamic是这样输入的：

export default function dynamic<P = {}>(dynamicOptions: DynamicOptions<P> | Loader<P>, options?: DynamicOptions<P>): React.ComponentType<P>;

其中 P 是导入组件的 props

所以，dynamic期望得到Loader<P>==LoaderComponent<P>Promise<React.ComponentType<P>

你只需要告诉他道具是什么。像这样：

const Spinner = dynamic<{ inline?: boolean }>(
  () => import('components/ui/Spinner').then(mod => mod.Spinner)
)

或者

import { Spinner as StaticSpinner } from 'components/ui/Spinner'

const Spinner = dynamic<React.ComponentProps<typeof StaticSpinner>>(
  () => import('components/ui/Spinner').then(mod => mod.Spinner)
)

或将 Props 导出，然后：

import { Props as SpinnerProps } from 'components/ui/Spinner'

const Spinner = dynamic<SpinnerProps>(
  () => import('components/ui/Spinner').then(mod => mod.Spinner)
)

Answer 2

React.FC@brc-dd 是对的，只需用类型定义组件即可，

export const Spinner: React.FC<Props> = ({inline}) => {}

虽然很少解释为什么它会这样工作：

dynamic是这样输入的：

export default function dynamic<P = {}>(dynamicOptions: DynamicOptions<P> | Loader<P>, options?: DynamicOptions<P>): React.ComponentType<P>;

所以它期望你返回React.ComponentType<P>，这意味着：

type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;

并且FunctionComponent是：

interface FunctionComponent<P = {}> {
        (props: PropsWithChildren<P>, context?: any): ReactElement<any, any> | null;
        propTypes?: WeakValidationMap<P>;
        contextTypes?: ValidationMap<any>;
        defaultProps?: Partial<P>;
        displayName?: string;
    }

所以你必须有带children钥匙的道具。如果你不想弄乱你的组件接口并且它实际上不接受子组件，那么你可以只输入children?: never;组件 Props 接口。