Wikipedia: Immutable object
By default, arrays and maps are mutable. The built-in immutable() returns a deeply immutable copy of any value. Attempting to modify it causes a runtime error.
fmt := import("fmt")nums := [1, 2, 3]
nums[0] = 99
fmt.println(nums)frozen := immutable([10, 20, 30])
fmt.println(frozen)
fmt.println(frozen[1])config := immutable({host: "localhost", port: 5432})
fmt.println(config["host"])
fmt.println(config["port"])data := immutable({users: ["alice", "bob"], count: 2})
fmt.println(data["users"])try it
[99, 2, 3] [10, 20, 30] 20 localhost 5432 ["alice", "bob"]