How to loop over Firestore array values in Cloud Function

Question

I'm stuck at trying to get a cloud function to loop over the values of an array in my Cloud Firestore. I have searched stack overflow but I couldn't find a solution yet. My Firestore structure looks as follows:

And my Cloud Function in Jacascript:

exports.createdEnv = functions.firestore.document('environments/{environmentName}')
.onCreate(async snapshot => {

const environmentName = snapshot.id;
const days = db.collection(environmentName);
const batch = db.batch();

        ['2020-02-06', '2020-02-07', '2020-02-08'].forEach((day) => {
        const documentReference = days.doc(day);
        batch.set(documentReference, {});

        //this is where I'm stuck
        const dataMachines = snapshot.data().machineNames;
        for (const value in dataMachines) {
        const valueMachine = dataMachines[value];
        console.log(snapshot.get('machineNames')[0]);
        snapshot.get('machineNames').forEach((value) => {

        //I want each value of the array to be set as subcollection below
        const hoursReference = documentReference.collection(value);
        const dataMap = {   '001': '08:00-09:00',
                            '002': '09:00-10:00',
                            '003': '10:00-11:00',
                            '004': '11:00-12:00',
                            '005': '12:00-13:00',
                            '006': '13:00-14:00',
                            '007': '14:00-15:00',
                            '008': '15:00-16:00',
                            '009': '16:00-17:00',
                            '010': '17:00-18:00',
                            '011': '18:00-19:00',
                            '012': '19:00-20:00',
                            '013': '20:00-21:00',
                            '014': '21:00-22:00',
                                                    };
        Object.keys(dataMap).forEach((hour) => {
            batch.set(hoursReference.doc(hour), {
                hour: dataMap[hour],
                reserved: '',
                name: '',
                date: '',
            });
        });

        });

        }

    });

    return batch.commit()
    .then(() => {console.log('ok'); return null })
    .catch((err) => {console.log(err); });
});

I have been stuck at this for a while and I feel like I'm missing something or forgetting something. If anyone could point me in the right direction that would be great!

Could you explain in more detail what you exactly want to do. It is a bit difficult to understand. Firstly, why do you do batch.set(documentReference, {}); You don't pass any (data) value to set(). Secondly, can you give an example of the expected result of your Cloud Function: which documents and collections are created with which content. Thanks! — Renaud Tarnec
– Renaud Tarnec, Commented Feb 6, 2020 at 10:15
Of course! The function creates a new collection with the environmentName as name. In that collection the function sets 3 documents; 2020-02-06, 2020-02-07, 2020-02-08. Then each of these documents should have subcollections with the names of the values from the array. If I substitute ‘value’ in the hoursReference with a simple string then a subcollection is created without problem. — Lorence Cramwinckel
– Lorence Cramwinckel, Commented Feb 6, 2020 at 10:30

Renaud Tarnec · Accepted Answer · 2020-02-06 11:27:07Z

3

if I have correctly understood your goal, the following should work:

//....
const dataMachines = snapshot.data().machineNames;

dataMachines.forEach(machineName => {

    const hoursReference = documentReference.collection(machineName);

    //....

})

//....

The call to snapshot.data() returns a JavaScript Object in which the machineNames property is an Array. You can check it with console.log(Array.isArray(dataMachines));.

Therefore you just have to use forEach() to get the different values stored in the Array.

Side Note: You will find in the following SO answer several other possible approaches to loop through a JavaScript Array.

answered Feb 6, 2020 at 11:27

Renaud Tarnec

83.4k10 gold badges99 silver badges130 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Lorence Cramwinckel Over a year ago

Thank you, this is great! The link to the other SO answer is also super useful, again thank you so much!

Collectives™ on Stack Overflow

How to loop over Firestore array values in Cloud Function

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related