typescript)Error Type 'x' is not assignable to type 'y'.

정의되어 있는 타입 y에 x를 할당할 수 없다는 error이다.

예시

export const searchRepositories = (term: string) => {
  return async (dispatch: Dispatch<Actions>) => {
    dispatch({
      type: ActionType.SEARCH_REPOSITORIES,
    })

    try {
      const {data} = await axios.get('https://registry.npmjs.org/-/v1/search',{
        params: {
          text: term
        }
      })
      const packageData = data.objects.map((result: any) => {
          return result.package
      })
      dispatch({
        type: ActionType.SEARCH_REPOSITORIES_SUCCESS,
        // error : Type 'number' is not assignable to type 'string[]'
        payload: 133131313 
      })
    }catch(err) {
      if(err instanceof Error){
        dispatch({
          type:ActionType.SEARCH_REPOSITORIES_ERROR,
          // // error : Type 'string[]' is not assignable to type 'string'
          payload:['hi']
        })
      }
    }
  }
}

Dispatch로 정의한 타입은 다음과 같다.

interface SearchRepositoriesAction {
  type: ActionType.SEARCH_REPOSITORIES
}

interface SearchRepositoriesSuccessAction {
  type : ActionType.SEARCH_REPOSITORIES_SUCCESS
  payload: string[]
}

interface SearchRepositoriesErrorAction {
  type: ActionType.SEARCH_REPOSITORIES_ERROR
  payload: string
}



export type Actions =  SearchRepositoriesAction | SearchRepositoriesSuccessAction | SearchRepositoriesErrorAction