How to create recursive types

Short answer

Recursive types reference themselves within their definition. In TypeScript, you can create recursive interfaces and type aliases to model nested data structures.

Steps

1. Define a tree node: interface TreeNode { value: string; children: TreeNode[]; }
2. Define a linked list: type LinkedList<T> = T & { next: LinkedList<T> } | null;
3. Model nested JSON: type JSONValue = string | number | boolean | null | JSONValue[] | { [key: string]: JSONValue };
4. Use interface for object shapes to avoid circular alias limitations.
5. Test recursive types with sample data.

Tips

• Interfaces support recursion more naturally than type aliases in older TypeScript versions.
• Tail-recursion optimization on conditional types (TypeScript 4.5+) helps deep recursive instantiations.

Common issues

• Excessively deep recursion causes Type instantiation is excessively deep and possibly infinite errors.
• Recursive types with conditional logic may need careful base-case design.