sample.ts

private visitNode(node: Node): void {
   if (isClassDeclaration(node)) {

      console.log("Hi class:", node.name);

   }
   
  node.forEachChild(child => this.visitNode(child));

}

const program = createProgram(["file.ts"]);

const sourceFile =program.getSourceFile("file.ts");

visitNode(sourceFile);