javascript - Vitest error No <functionName> export is defined on the <path> - Stack Overflow

admin管理员组

文章数量:1344317

Here i have a function which formats Weatherdata fetched from an api, i want to mock this api call to have consistent weather data to only test the pure formatting function weatherApiController.ts

import { getWeatherData, formatWeatherData} from '../controller/weatherApiController'
import { describe, expect, vi, test } from 'vitest'



export async function formatWeatherData(start: String, end: String){
    let data = await getWeatherData(start, end)
    let formattedTemps = []
    for(let i = 0; i < data.days.length; i++){
        formattedTemps.push({datetime: data.days[i]['datetime'], tempmax: data.days[i]['tempmax'], tempmin: data.days[i]['tempmin']})
    }
    console.log(formattedTemps);
    
    return formattedTemps
}


export async function getWeatherData(start: String, end: String) {
    try{
        let response = await fetch(`/${start}/${end}?unitGroup=metric&include=days%2Ccurrent&key=<apiKey>&contentType=json`);
        if(!response.ok){
            throw new Error(`HTTP Error! Status: ${response.status}`);
        }
        let data = await response.json()
        console.log(data);
        
        return data
    }catch(error){
        console.error(error)
        return null
    }
}

weatherApiController.test.ts

test('mock3', async()=> {
    let expected = [
  { datetime: '2023-03-12', tempmax: 10.4, tempmin: -0.2 },
  { datetime: '2023-03-13', tempmax: 15.4, tempmin: 9.1 }
]
    vi.mock('../controller/weatherApiController.ts', async() => {
        const actual = await vi.importActual("../controller/weatherApiController.ts")
        return {
          actual,
          getWeatherData: async() => {
            number: 3
          },
          formatWeatherData: async() => {
            number:4
          }
        }
      });
      const result = await formatWeatherData('2023-03-12', '2023-03-13')
      expect(result).toEqual(expected)
})

This is the error i get Error: [vitest] No "formatWeatherData" export is defined on the "../controller/weatherApiController.ts" mock. Did you forget to return it from "vi.mock"? If you need to partially mock a module, you can use "vi.importActual" inside:

i appreciate any help!

I tried to mock the API call to get consistent weather data. I expected to have a constant return value of the function.

Here i have a function which formats Weatherdata fetched from an api, i want to mock this api call to have consistent weather data to only test the pure formatting function weatherApiController.ts

import { getWeatherData, formatWeatherData} from '../controller/weatherApiController'
import { describe, expect, vi, test } from 'vitest'



export async function formatWeatherData(start: String, end: String){
    let data = await getWeatherData(start, end)
    let formattedTemps = []
    for(let i = 0; i < data.days.length; i++){
        formattedTemps.push({datetime: data.days[i]['datetime'], tempmax: data.days[i]['tempmax'], tempmin: data.days[i]['tempmin']})
    }
    console.log(formattedTemps);
    
    return formattedTemps
}


export async function getWeatherData(start: String, end: String) {
    try{
        let response = await fetch(`https://weather.visualcrossing./VisualCrossingWebServices/rest/services/timeline/Wermelskirchen/${start}/${end}?unitGroup=metric&include=days%2Ccurrent&key=<apiKey>&contentType=json`);
        if(!response.ok){
            throw new Error(`HTTP Error! Status: ${response.status}`);
        }
        let data = await response.json()
        console.log(data);
        
        return data
    }catch(error){
        console.error(error)
        return null
    }
}

weatherApiController.test.ts

test('mock3', async()=> {
    let expected = [
  { datetime: '2023-03-12', tempmax: 10.4, tempmin: -0.2 },
  { datetime: '2023-03-13', tempmax: 15.4, tempmin: 9.1 }
]
    vi.mock('../controller/weatherApiController.ts', async() => {
        const actual = await vi.importActual("../controller/weatherApiController.ts")
        return {
          actual,
          getWeatherData: async() => {
            number: 3
          },
          formatWeatherData: async() => {
            number:4
          }
        }
      });
      const result = await formatWeatherData('2023-03-12', '2023-03-13')
      expect(result).toEqual(expected)
})

This is the error i get Error: [vitest] No "formatWeatherData" export is defined on the "../controller/weatherApiController.ts" mock. Did you forget to return it from "vi.mock"? If you need to partially mock a module, you can use "vi.importActual" inside:

i appreciate any help!

I tried to mock the API call to get consistent weather data. I expected to have a constant return value of the function.

• javascript
• typescript
• unit-testing
• mocking
• vitest

Share Improve this question Follow asked Mar 30, 2023 at 16:46 LePaLePa 5111 silver badge22 bronze badges 1

• Did you ever find a solution for this? I am running into the same issue after implementing the suggested syntax from Vitest. – JacobB Commented May 4, 2023 at 18:39

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 9

I had a similar issue where my mock looked like this:

vi.mock('@/api/Client', () => {
    const API = VueMocks.API
    return API
})

and vitest was erroring with

Error: [vitest] No "default" export is defined on the "@/api/Client" mock. 
Did you forget to return it from "vi.mock"?
If you need to partially mock a module, you can use "vi.importActual" inside:

vi.mock("@/api/Client", async () => {
  const actual = await vi.importActual("@/api/Client")
  return {
    ...actual,
    // your mocked methods
  },
})

Reading up the vitest docs, There was a warning in the vitest document under vi.Mock that said:

WARNING

If you are mocking a module with default export, you will need to provide a default key within the returned factory function object. This is an ES modules-specific caveat, therefore jest documentation may differ as jest uses CommonJS modules. For example, ts

vi.mock('./path/to/module.js', () => {   return {
    default: { myDefaultKey: vi.fn() },
    namedExport: vi.fn(),
    // etc...   } })

In my actual @/api/Client file, which was a ts file, it looked like this

export export class API { ... }

<Stuff>

export default new API(shallowReactive)

So in my case I had to have a default that was returned, in addition to the module I wanted returned.

I had to do something like this

vi.mock('@/api/Client', () => {
    const API = VueMocks.API
    return {
        default: { ...API },
    }
})

Where for me VueMocks.API was a var object I had made myself that specified all the mocks required by the API already.

In your case, you would probably have to do something like

vi.mock('../controller/weatherApiController.ts', async() => {
    const actual = await vi.importActual("../controller/weatherApiController.ts")
    return {
      ...actual,
      getWeatherData: async() => {
        number: 3
      },
      formatWeatherData: async() => {
        number:4
      }
    }

Since the exports in your file above are export async function formatWeatherData([...]) and export async function getWeatherData([...])

It also looked like you forgot to add the ... for copying the value of actual, because in yours it is return { actual when it should be return { ...actual

本文标签： javascriptVitest error No ltfunctionNamegt export is defined on the ltpathgtStack Overflow