如何使用 Object.assign 更新嵌套对象

Question

I want to use Object.assign overwrite a nested object within an object.

for example if I have an object like

let obj = {2: {fruit: "orange", animal: "dog"} 3: {fruit: "apple", animal: "cat"}}

How would I use Object.assign to update for example the second object with key 3 to {fruit: "banana", animal: "pig"} but still maintain the structure of obj ?

This solution should be dynamic so if for example the next time, the first object with key 2 could be updated to {fruit: "strawberry", animal: "bat"}

EDIT

So the new returned object will be

{2: {fruit: "orange", animal: "dog"} 3: {fruit: "banana", animal: "pig"}}

EDIT2

Solution needs to be dynamic

EDIT3

Seems as though this can't be achieved with just Object.assign so is there a deep copy solution to do this?

Answer 1

First thing to do is not call your object "Object":

let obj = {2: {fruit: "orange", animal: "dog"} 3: {fruit: "apple", animal: "cat"}};

Then you can use Object.assign() on obj[3] :

Object.assign(obj[3], {fruit: "banana", animal: "pig"});

(If you use "Object" as a variable name, you lose access to the global "Object", making Object.assign impossible to use.)

If you want a whole new object, you'll have to make copies of the nested objects because Object.assign() performs a shallow copy only. In your case that's pretty easy, but in general making a deep copy can be very complicated:

let newObj = {
  2: Object.assign({}, obj[2]),
  3: {fruit: "banana", animal: "pig"}
};

Answer 2

Try this below:

let data = {2: {fruit: "orange", animal: "dog"} 3: {fruit: "apple", animal: "cat"}}

Object.assign(data[3], {fruit: "banana", animal: "pig"});

console.log(data)