Use the build in function structuredClone() to copy all kind of complex JS types.
Official documentation: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#supported_types
Comparison to other copy techniques like spread or json.stringify: https://www.builder.io/blog/structured-clone
The user tim-montague posted a great overview on the different deep copy techniques on stackoverflow:
In my case I had an array of objects which I wanted to copy without reference, therefore I used the option in the middle.
const copy = JSON.parse(JSON.stringify(myArray))
# Another way using ES6 Syntax
const copy = myArray.map(object => ({ ...object }))