Using the TypeScript type checker to see if two types are assignable

Question

I\'m building a small script that scans for all interfaces that have a member of a given type using the TypeScript Compiler API, of which the source can be found here. I ins

Answer 1

I've found it: seems like it is currently not possible:

• Expose isTypeAssignableTo in TypeChecker?
• Proposal: Type Relationship API
• Assignability checks in API

I created my own fork which exposes this function. I will try to maintain it so if anyone is interested he or she can just use the fork until upstream follows.

Answer 2

Typescript is just a superset of JavaScript. You cannot make 'on the run' verifications with TypeScript that you are not able to do with Javascript.

JavaScript does not have "classes" or "inherit" information. It only know creating objects and verify if an instance is instance of an object.

JavaScript does have a method called 'instaceof' that verifies if a instance is instance of a class. for instance.

var x = new ASTKind.Multiplication
x instanceof ASTKind.Multiplication // will return true
x instanceof AST // sill also return true