I don't want to freeze the object, I want to have a handle that doesn't allow me to modify the object. (Whether that would be at all possible in JS is another question.)
So
let foo = {field:1};
immutable let bar = foo;
bar.field = 2; // error
foo.field = 3; // ok
This is what I actually want when I think "const". I don't really care that you can reuse a variable, or re-seat a value. What I care about is that I recieve an object and sometimes want to modify it, and sometimes I want to make sure it stays the same. Maybe somebody else holds a reference and I don't want to surprise them.
(The inverse problem is when I have a function that takes something like a string or a number, and I want to change that from within the function. There is no way to pass a value type by reference. You have to encapsulate the value in an object and pass that. It would be cool if you could say something like `function double(ref x) { &x = x*2; }`.)
So
This is what I actually want when I think "const". I don't really care that you can reuse a variable, or re-seat a value. What I care about is that I recieve an object and sometimes want to modify it, and sometimes I want to make sure it stays the same. Maybe somebody else holds a reference and I don't want to surprise them.(The inverse problem is when I have a function that takes something like a string or a number, and I want to change that from within the function. There is no way to pass a value type by reference. You have to encapsulate the value in an object and pass that. It would be cool if you could say something like `function double(ref x) { &x = x*2; }`.)