CODEWITHSUNDEEP
javascriptfirebase-realtime-databasepromisegoogle-cloud-functionsfirebase-cli
oTwo
oTwo

Reputation: 285

Promises must be handled appropriately in Firebase CLI data request

I am trying to read data from a node after an onCreate event has been triggered in another node. Data from these nodes would then be sent to a Google Sheet. While there is no error reported when I build the function, there is a deployment error where the message "Promises must be handled appropriately" is shown. Here is my function:

export const copyAcceptanceToSheet = functions.database.ref('/****/{****Id}/****').onCreate(async (snapshot, context) => {

    const orderId = snapshot.ref.parent?.key
    const pharmacy = snapshot.val()
    const timeCreated = new Date

    const ****Base = admin.database()
    const acceptRef = ****Base.ref('/*****/'+orderId+'/*****'+pharmacy);

    acceptRef.once('value').then(async function (snapshot2) {
        try{
            const price = snapshot2.child('****').val()

            await jwtAuthPromise
            await sheets.spreadsheets.values.append({
            auth: jwtClient,
            spreadsheetId: spreadsheetId,
            range: '****Update!A:D',  // update this range of cells
            valueInputOption: 'RAW',
            requestBody: { values: [[timeCreated, price, pharmacy]]}
            }, {})
        }
        catch(error){
            console.log(error)
        }

    })

})

The error message is for the line 

 acceptRef.once('value').then(async function (snapshot2)

Upvotes: 0

Views: 121

Answers (1)

Doug Stevenson
Doug Stevenson

Reputation: 317372

As explained in the documentation, background functions must return a promise that resolves when all asynchronous work is complete. This means that you must deal with any promises returned by API calls that work asynchronously. All Firebase APIs are asynchronous in this way. Right now, you function ignores the promise returned by once().then().catch(). Simply calling then or catch on the promise doesn't fully "handle" the promise - they are just attaching callbacks.

Since you are using async/await, there is no need to even use then and catch. Just await the promise returned by once() and continue dealing with the result.

const snapshot2 = await acceptRef.once('value');
const price = snapshot2.child('****').val()
...

Upvotes: 1

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