MongoDB Object Key With ES6 Template String

I'm trying to update an array in my collection with this: var str = 'list.0.arr'; db.collection('connect').update({_id: id}, {$push: { `${str}`: item}}); This exact string

Solution 1:

Template literals cannot be used as key in an object literal. Use a computed property instead:

db.collection('connect').update({_id: id}, {$push: {[str]: item}}); 
//                                                  ^^^^^

See also Using a variable for a key in a JavaScript object literal

Solution 2:

Create the update document with the string as key prior to using it in the update:

var str = "list.0.arr",
    query = { "_id": id },
    update = { "$push": {} };
update["$push"][str] = item;
db.collection('connect').update(query, update);