Javascript Cloud Firestore：使用动态键更新嵌套对象中的字段
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Cloud Firestore: Update fields in nested objects with dynamic key
提问by Brieuc
following the official documentation of firestore :
遵循 firestore 的官方文档：
{
name: "Frank",
favorites: { food: "Pizza", color: "Blue", subject: "recess" },
age: 12
}
// To update favorite color:
db.collection("users").doc("frank").update({
"favorites.color": "Red"
})
I would like to use a dynamic key instead of color.
我想使用动态键而不是颜色。
db.collection("users").doc("frank").update({
"favorites[" + KEY + "].color": true
});
this is of course not possible and will throw an error.
这当然是不可能的，并且会抛出错误。
I've been trying to do this :
我一直在尝试这样做：
db.collection("users").doc("frank").update({
favorites: {
[key]: {
color": true
}
}
});
It is actually updating with the right key but unfortunately, it is overwriting the other keys (they are being deleted).
它实际上是使用正确的键进行更新，但不幸的是，它正在覆盖其他键（它们正在被删除）。
回答by Brieuc
I found the solution inspired by a firebase solution (replacing "/" by ".").
我找到了受 firebase 解决方案启发的解决方案（将“/”替换为“.”）。
var usersUpdate = {};
usersUpdate[`favorites.${key}.color`] = true;
db.collection("users").doc("frank").update(usersUpdate);
回答by Georg Hackenberg
This solution worked for me:
这个解决方案对我有用：
db.collection('users').doc('frank').update({
['favorites.' + key + '.color']: true
});
回答by Ronnie Royston
You can update specific fields of variable(ly) named nested objects like below.
您可以更新变量（ly）命名嵌套对象的特定字段，如下所示。
ref.set({
name: "Frank",
favorites: { food: "Pizza", quantity: 2 }
});
//now the relevant update code
var name = "favorites";
var qty = 111;
var update = {};
update[name+".quantity"] = qty;
ref.update(update);
回答by undefined
Just a note about a potential pitfall: After discovering that you can update nested fields using a dot syntax, I tried using set()the same way, since I needed it to work whether the object already exists or not:
关于潜在陷阱的说明：在发现您可以使用点语法更新嵌套字段后，我尝试使用set()相同的方式，因为无论对象是否已经存在，我都需要它来工作：
var updateObj = {['some.nested.property']: 9000};
docRef.set(updateOb, {merge: true});
Unfortunately, this doesn't work – it sets a property whose key is some.nested.propertyinstead. Inconsistent, but okay.
不幸的是，这不起作用——它设置了一个属性，其键是some.nested.property。不一致，但还好。
Fortunately, it appears that set(updateObj, {merge: true})does a deep merge, so if you construct your update object as a fully nested object, your nested objects will also be properly merged:
幸运的是，它似乎进行set(updateObj, {merge: true})了深度合并，因此如果您将更新对象构造为完全嵌套的对象，您的嵌套对象也将被正确合并：
// create the object
db.doc('testCollection/doc').set({p1: {['p2']: {p3: true}}}, {merge: true})
// update the existing object
db.doc('testCollection/doc').set({p1: {['p2']: {p4: true}}}, {merge: true})
// result is now this:
{ p1: { p2: { p4: true, p3: true } } }
