reactjsreact-typescriptreact-queryjson-servertanstackreact-query

React Query doesn't fetch API - causing data to return 'undefined'


I've been trying to GET data from the JSON-server using @tanstack/react-query in the same code pattern that worked for me in another project. However, this time the function seems to have not been called for some reason, causing the data to return 'undefined'. What am I missing here?

Here is the code in the component task-list.tsx:

import { fetchAllTasks } from "../../api/tasks-api"
import TaskItem from "./task-item/task-item"

import style from './task-list.module.scss'



const TaskList = () => {

    // This supposed to work, but isn't!
    const { data: tasks, isLoading } = fetchAllTasks()
    

    // This logs: undefined
    console.log('tasklists - fetchAllTasks:', tasks) 


    return (
        <div className={`${style['TaskList']}`}>
            <ul>
                {
                    !isLoading && tasks && tasks?.length < 1 ?
                        <p className={`${style['no-task']}`}>
                            +++ Task List is Empty +++
                        </p>
                        :
                        tasks?.map((task) =>
                            <TaskItem
                                key={task.toString()}
                                atom={task}
                            />
                        )
                }
            </ul>
        </div>
    )
}

export default TaskList

Here is the fetchAllTasks() function in task-api.ts:

import { useQuery } from "@tanstack/react-query"
import axios from "axios"
import { Task } from "../types"


export const fetchAllTasks = () => {

    return useQuery({
        queryKey: ['tasks'],
        queryFn: async () => {
            const response = await axios.get('http://localhost:3100/tasks')
            const data: unknown = await response.data()
            
            // This doesn't appear in the console log at all
            console.log('data: ', data)


            return data as Task[]
        }
    })
}

Here is what shows up in the browser:

The bug as shown in the browser

Here is the response from the backend:

enter image description here

Here is how the network tab of the browser looks like after a page refresh.

enter image description here

enter image description here

The link to the project repo: https://github.com/iceyisaak/todoapp/tree/tanstack-query/src

Help is very much appreciated :)


Solution

  • Axios returns data as property, so you do not invoke data as method on the response object and because it is a property you do not need to use await.

     const response = await axios.get('http://localhost:3100/tasks')
     const data: unknown = response.data