(TS - Redux) 如何将状态 属性 初始化为 null：类型 'UserData' 不可分配给类型 'null'

Question

我遇到此错误：类型 'UserData' 无法分配给类型 'null'。

我将用户状态 属性 定义为 user: UserData | null;... 所以我不明白为什么它不允许我将 属性 初始化为 null 然后为它分配一个类似 UserData 的值： Error Console

import { createSlice, PayloadAction } from "@reduxjs/toolkit";
import { UserData } from "../../types/user";

interface AppState {
  user: UserData | null;
}

const appSlice = createSlice({
  name: 'app',
  initialState: { user: null },
  reducers: {
    loadUserIntoApp: {
      reducer(state, action: PayloadAction<UserData>) {
        state.user = action.payload; // This is the line with an error
      }
    }
  }
})

Answer 1

您应该将 AppState 接口推断为 initialState

import { createSlice, PayloadAction } from "@reduxjs/toolkit";
import { UserData } from "../../types/user";

interface AppState {
  user: UserData | null;
}

const appSlice = createSlice({
  name: 'app',
  initialState: AppState = { user: null },
  reducers: {
    loadUserIntoApp: {
      (state, action: PayloadAction<UserData>) => { //you should add the reducer like this
        state.user = action.payload;
       }
    }
  }
})

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