typescript-json-schema/test/programs/strict-null-checks/main.ts

typescript-json-schema generates JSON Schema files from your Typescript sources

class MyObject {
     val: number;
     valNullable: number | null;
     valUndef: number | undefined;
     valOpt?: number;

     valTrueOpt?: true;
     valTrueOrNull: true|null;
     valTrue: true|true; // twice to check that it will appear only once
}