Why does my function return undefined?

6 replies

Last updated: Aug 23, 2022

Hi guys i need some help on why my function returns // undefined.

AI Update

I'd be happy to help debug why your function is returning undefined! Since you didn't provide specific code, let me cover the most common scenarios where this happens in Sanity:

If you're working with Sanity Functions (serverless):

Sanity Functions need to explicitly return values. Common issues include:

1. Missing return statement:

export default async function(event, client) {
  const result = await client.fetch('*[_type == "post"]')
  // Missing return! Add:
  return { statusCode: 200, body: result }
}

2. Async/await issues: Make sure you're awaiting promises and returning the result:

export default async function(event, client) {
  const data = await someAsyncOperation() // Don't forget await
  return { statusCode: 200, body: data }
}

Check the Sanity Functions quickstart guide for proper function structure and use the logging capabilities to debug what's happening.

If you're working with GROQ queries:

1. Projection issues:

// This returns undefined if field doesn't exist
const query = '*[_type == "post"][0].nonExistentField'

// Better - handle missing fields:
const query = '*[_type == "post"][0]{ title, "slug": slug.current }'

2. Client fetch not awaited:

// Wrong:
const data = client.fetch('*[_type == "post"]') // Returns Promise, not data

// Correct:
const data = await client.fetch('*[_type == "post"]')

If you're working with Studio plugins or custom components:

1. Document field access:

// Wrong - accessing nested field that doesn't exist
const value = document.some.nested.field // undefined if path doesn't exist

// Better - use optional chaining:
const value = document?.some?.nested?.field

2. Hook dependencies:

// In React components, make sure hooks return before accessing data:
const {data} = useSomeHook()
if (!data) return null // Guard against undefined
return <div>{data.title}</div>

General debugging tips:

Add console.logs or use the debugger to inspect what your function is actually receiving and returning
Check the logs - Sanity Functions have built-in logging you can inspect
Verify your data structure - use the Vision plugin in Studio to test GROQ queries
Check for typos in field names or property access

If you can share your specific code snippet, the context (where this function runs), and any error messages, I can provide more targeted help!

Show original thread

6 replies

Hey User. 👋• Please kindly group your Slack messages into a single message so we can use a unique thread to help you.
• Try wrapping your code in triple backticks ``` so we have a proper code snippet which is easier to read. :)
• Share a bit more information about which function is not providing the desired result.

const InternationalData = async () => {

  const response = await fetch(COUNTRY_API_URL)
  const mydata = await response.json()
  await mydata.records.map(transformCountry)
//  console.log(records)
}

InternationalData()

const appendToFile = (document) => {
  const docAsNewLineJson = `${JSON.stringify(document)} \n`
  fs.appendFileSync('ready-for-import.ndjson', docAsNewLineJson, {flag: 'a+'})
}

const getCountryDetails = async (countryName) => {

  try{
    const res = await fetch(`<https://api.airtable.com/v0/app5Ol3fLrAFeVfXh/${countryName}?api_key=xxxxxxxx>`)
    const data = await res.json()
    // console.log(data)
    await data?.records?.map(recordsData)
  
  }catch(error){
    return(
      count('no data' + error)
    )
  }
}


  // //Fetching degree types
const res = await fetch(DEGREE_API_URL)
const data = await res.json()
const GeneralRec = data?.records.map(e => {return { _id: e.id, _type: 'englishDegree', name: e.fields.Name}})


const recordsData = async ({fields}) => {

  const schoolTypeID = await fields["English Type of Degree"]
  const sID = await schoolTypeID.find(id => id || null )

  const recs =   {
    schoolType: { _type: "reference", _ref: fields["Min Length"]},
    localWardedDegree: fields["Local Awarded Degree"],
    englishTypeDegree: await GeneralRec.find(e =>  e.name ? sID===e._id: null),
    Level: fields.Level,
    LocalInsName: fields["Local Ins. Name"],
    Notes: fields.Notes || null,
  }
  if(recs && !undefined){
    return recs
  }
 

}

const transformCountry = async (data) => {
  const countryID = data?.id?.toLowerCase()
  const countryName = data?.fields['Country (en)']
  const countrySlug = data?.fields?.slug 
  const records = await getCountryDetails(countrySlug) // returns undefined
  
 
  
  const country = {
    _type: 'Intcountry',
    _id: countryID,
    name: countryName,
    records: records // undefined
  }
  // appendToFile(country)
  // console.log(country)
  // return country
  
}

   await mydata.records.map(transformCountry)

You need to store the result of the map here. Unless your mapper is mutating each country individually but a) I wouldn’t recommend it and b) it doesn’t look like it does.

  // return country

The

transformCountry

function does not return anything because you commented out the return statement.

     await data?.records?.map(recordsData)

Your function doesn’t return anything because you’re not returning that statement. You’re mapping into the void and not returning anything.

Thank you so much

user F

. works perfectly, i get different outputs. i.e some data is returned well when i run the file, and on re-run i get different results.

Is it something you can help with.

Errrr, not without a bit more info. 😅

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