Value types in JavaScript · baby steps

A design exploration for user-defined value types in JavaScript, written by a TC39 contributor. It argues that JavaScript's primitive/object divide is too rigid and proposes 'value objects' — typed objects that are immutable and compared by field equality rather than identity. The post covers the problems with using plain objects for value-like data (aliasing, mutation, optimization barriers), explains why modeling user-defined value types on primitives doesn't scale, and proposes building on typed objects via a `.valueType()` transformer. Concrete examples show how struct and array value types would behave, including copy-out semantics and redefined `===` equality. Integration with ES6 Map and Set is also discussed.