Firestore - Using arrayUnion() to Add Arrays

Question

Firestore - Using arrayUnion() to Add Arrays

Is there a way to correctly pass an array to the firebase firestore arrayUnion() function?

I encountered an issue while attempting to pass an array and received the following error message:

Error

Error: 3 INVALID_ARGUMENT: Cannot convert an array value in an array value.

Example

let myArray = ["1", "2", "3"];

docRef.update({
    test: firebase.firestore.FieldValue.arrayUnion(myArray)
});

javascript firebase google-cloud-firestore

Answer 1

Answer №1

I finally stumbled upon the solution by utilizing Function.prototype.apply() as recommended in another helpful response on Stack Overflow.

Illustration of Function.prototype.apply()

let myArray = ["1", "2", "3"];

docRef.update({
    test: firebase.firestore.FieldValue.arrayUnion.apply(this, myArray)
});

Illustration of ECMAScript 6

utilizing the spread argument feature

let myArray = ["1", "2", "3"];

docRef.update({
    test: firebase.firestore.FieldValue.arrayUnion(...myArray)
});

By employing either of the aforementioned methods to pass an array, Firestore will solely append new elements that are not already present in the Firestore array.

For instance, executing the above code and then running the subsequent

let myArray = ["2", "3", "5", "7"];

docRef.update({
    test: firebase.firestore.FieldValue.arrayUnion(...myArray)
});

will only add "5" and "7" to the Firestore array. This approach is also effective for arrays containing objects.

Answer 2

I finally stumbled upon the solution by utilizing Function.prototype.apply() as recommended in another helpful response on Stack Overflow.

Illustration of Function.prototype.apply()

let myArray = ["1", "2", "3"];

docRef.update({
    test: firebase.firestore.FieldValue.arrayUnion.apply(this, myArray)
});

Illustration of ECMAScript 6

utilizing the spread argument feature

let myArray = ["1", "2", "3"];

docRef.update({
    test: firebase.firestore.FieldValue.arrayUnion(...myArray)
});

By employing either of the aforementioned methods to pass an array, Firestore will solely append new elements that are not already present in the Firestore array.

For instance, executing the above code and then running the subsequent

let myArray = ["2", "3", "5", "7"];

docRef.update({
    test: firebase.firestore.FieldValue.arrayUnion(...myArray)
});

will only add "5" and "7" to the Firestore array. This approach is also effective for arrays containing objects.

Firestore - Using arrayUnion() to Add Arrays

Answer №1

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