Spread syntax (...) - JavaScript | MDN
developer.mozilla.org
The spread (...) syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value pairs to the object being created.

Answer: create a new object with the properties of the two original objects using the spread operator.

The order you insert the objects into the new merged object determines which object’s properties take priority over the other.

Linked example:

const obj1 = { foo: "bar", x: 42 };
const obj2 = { foo: "baz", y: 13 };

const clonedObj = { ...obj1 };
// { foo: "bar", x: 42 }

const mergedObj = { ...obj1, ...obj2 };
// { foo: "baz", x: 42, y: 13 }

You can find more discussion here: https://stackoverflow.com/questions/171251/how-can-i-merge-properties-of-two-javascript-objects-dynamically