Array update operations (arrayUnion, arrayRemove) in Firebase - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a new item to the array field in Firestore using arrayUnion.

Firebase

docRef.update({ items: firebase.firestore.FieldValue.[1](['newItem']) });

Drag options to blanks, or click blank then click option'

AarrayUnion

BarrayRemove

Cincrement

Dset

Attempts:

3 left

💡 Hint

Common Mistakes

Using arrayRemove instead of arrayUnion.

Using set which replaces the whole field.

arrayUnion adds elements to an array field without duplicates.

2fill in blank

medium

Complete the code to remove an item from the array field in Firestore using arrayRemove.

Firebase

docRef.update({ tags: firebase.firestore.FieldValue.[1](['oldTag']) });

Drag options to blanks, or click blank then click option'

Aincrement

BarrayUnion

CarrayRemove

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using arrayUnion which adds instead of removes.

Using delete which deletes the whole field.

arrayRemove removes specified elements from an array field.

3fill in blank

hard

Fix the error in the code to correctly add multiple items to an array field using arrayUnion.

Firebase

docRef.update({ list: firebase.firestore.FieldValue.[1]('item1', 'item2') });

Drag options to blanks, or click blank then click option'

AarrayRemove

Bincrement

Cset

DarrayUnion

Attempts:

3 left

💡 Hint

Common Mistakes

Passing items as a single string instead of separate arguments.

Using arrayRemove which removes items.

arrayUnion accepts multiple arguments as separate items, not a single string.

4fill in blank

hard

Fill both blanks to update the array field by removing 'oldValue' and adding 'newValue'.

Firebase

docRef.update({ data: firebase.firestore.FieldValue.[1](['oldValue']) });
docRef.update({ data: firebase.firestore.FieldValue.[2](['newValue']) });

Drag options to blanks, or click blank then click option'

AarrayRemove

BarrayUnion

Cset

Dincrement

Attempts:

3 left

💡 Hint

Common Mistakes

Using arrayUnion for removal.

Trying to do both in one call incorrectly.

Use arrayRemove to remove and arrayUnion to add elements in separate update calls.

5fill in blank

hard

Fill all three blanks to remove 'x', add 'y', and add multiple items 'a' and 'b' to the array field.

Firebase

docRef.update({ arr: firebase.firestore.FieldValue.[1](['x']) });
docRef.update({ arr: firebase.firestore.FieldValue.[2](['y']) });
docRef.update({ arr: firebase.firestore.FieldValue.[3]('a', 'b') });

Drag options to blanks, or click blank then click option'

AarrayRemove

BarrayUnion

Dset

Attempts:

3 left

💡 Hint

Common Mistakes

Using set which replaces the whole array.

Trying to remove with arrayUnion.

Use arrayRemove to remove, and arrayUnion to add single and multiple items.