ts-type-visitor

Typescript type visitor

It's a function that takes a ts.TypeChecker and a ts.Type and traverses the type building easy-to-use TypeModel

const typeVisitor = (checker: TypeChecker, type: Type): TypeModel => {...}
 
export type TypeModel = 
  | TypeModelString
  | TypeModelNumber
  | TypeModelUnion
  | ...
 
export interface TypeModelString {
  readonly kind: "string";
}
 
export interface TypeModelNumber {
  readonly kind: "number";
}
 
export interface TypeModelUnion {
  readonly kind: "union";
  readonly types: TypeModel[];
}
 
...

It's different from Typescript compiler API built-in model by the next properties

1. It has a kind field (string, number, object) which is string literal union so it allows you to do exhaustive checks
2. It simplifies the API itself, there's no methods, flags and this kind of stuff, only kind and additional data
3. It has a built-in special types, array and tuple namely, that is kinda tricky to detect using vanilla compiler API

Basically you want to use it along with a compiler API, just using it for the ts.Type, and using Typescript compiler API for everything else, e.g. emitting new code, analyzing AST etc.

Installation

npm i -D ts-type-visitor
# or 
yarn add --dev ts-type-visitor