Firestore: Update fields in nested objects

Question

How can one update fields in a document's nested object? The documentation indicated dot notation but how do you achieve the update with a variable as the object name?

Structure is like: collection("fruits").doc("as867f56asd")

name: "banana"
abc-variable: 
    description:"blah"
    qty: 1

I want to update document as867f56asd's abc-variable.qty = 2

My JavaScript requires the use of a variable for the object name.

I can't figure out bracket notation for the update. Is .set{merge:true} req'd?

Here is the code I've tried so far (rough paste):

qty = evt.target.value;
//create a string
var obj = firebase.firestore.FieldPath(item).quantity;
//str = item + '.quantity';
//obj[str] = qty;
// var myUpdate = {};
// myUpdate['${item}.quantity'] = qty;
//var obj = [item]["quantity:"] = qty;
console.log("item is " + item);
//var obj = {"'" + item + "'.quantity" : qty};
//obj[item]["quantity"] = qty;
console.log("qty is " + qty);
orderRef.update (
    {obj:2}
    //{"quantity":qty}
    //[item + '.quantity']: qty
    //[`favorites.${key}.color`] = true
    // ['${item}.quantity'] : qty
    //[`hello.${world}`]:
    //{[objname]}.value = 'value';
    //['favorites.' + key + '.color']: true
    //[item]["quantity"] = qty // err:reqd 2 args
    //item["quantity"] = qty
    //"favorites.color": "Red"
    //{"`item`.quantity": qty}
    //{"quantity":qty}
)

user_209103 · Answer

If the update you're trying to do:

let qty = 2
orderRef.update({"abc-variable.qty": qty});

But then where abc-variable is the value of a variable, you would do:

let qty = 2
let variable = "abc-variable";
var values = {};
values[variable] = qty;
orderRef.update(values);

Update

This code updates only the favorites:

var variableObjectName = "favorites";
var qty = Date.now(); // just so it changes every time we run
var field = {quantity:qty};
var obj = {};
obj[variableObjectName] = field; 
ref.update(obj);

It does not remove any other properties on the document.

Update 2

To update a single field in a nested objected, use . to address the field:

ref.update({ "favorites.quantity": Date.now() });

See the documentation on how to update fields in nested objects.

Update 3

To perform a deep update of a field whose name is stored in a variable:

var name = "favorites";
var update = {};
update[name+".quantity"] = Date.now();
ref.update(update);

Once again shown in: https://jsbin.com/wileqo/edit?js,console

Firestore: Update fields in nested objects

1 Answers