Closed
Description
Suggestion
π Search Terms
Inference
Template Literal Types
Subtypes
β Viability 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, new syntax sugar for JS, etc.)
- This feature would agree with the rest of TypeScript's Design Goals.
β Suggestion
I'd like to be able to infer a subtype from a template literal type. For example:
const canExtend: `myString.${number}` extends `${infer Key}.${number}` ? true : false = true;
π Motivating Example
This will allow cross-matching between Values and Paths when traversing an object with dot notation.
π» Use Cases
See line 35, in this Playground