Nominal typing support like opaque type

[xiaoxiangmoe]

Search Terms

Nominal typing/ opaque type

Suggestion

support https://flow.org/en/docs/types/opaque-types/

Use Cases

Examples

// @flow
opaque type ID = string;

function identity(x: ID): ID {
  return x;
}
export type {ID};

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

[jack-williams]

Duplicate of #202, related #4895.

[typescript-bot]

This issue has been marked as a duplicate and has seen no activity in the last day. It has been closed for automatic house-keeping purposes.