Registry / serialization / typescript-rtti

typescript-rtti

library0.9.6jsnpmunverified

A TypeScript transformer and runtime reflection library that emits comprehensive runtime type information (RTTI) for classes, interfaces, functions, and call sites. Current stable version is 0.9.6 (release candidate quality). Requires TypeScript 4.8–5.1 and reflect-metadata. Differentiators: supports emission for a wide range of TypeScript concepts including mapped types (partial), ES modules and CommonJS, isomorphic across browser and Node.js, and compatible with existing design:* metadata. Alternates (e.g., tst-reflect) may lack breadth of type support or require heavier compiler customizations.

serialization

npm install typescript-rtti

github ↗package ↗

INSTALL

IMPORT

SIG · TYPESCRIPT-RTTI

typescript-rtti

serializationjavascriptv0.9.6

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

reflect

✓ import { reflect } from 'typescript-rtti'

✗ import { Reflect } from 'typescript-rtti'

reflect is a named export, not a default export. TypeScript type-only import: import type { reflect } from 'typescript-rtti'.

CallSite

✓ import { CallSite } from 'typescript-rtti'

✗ import { callsite } from 'typescript-rtti'

CallSite interface for capturing call-site type info; case-sensitive.

Reflector

✓ import { Reflector } from 'typescript-rtti'

✗ import Reflector from 'typescript-rtti'

Reflector is a class, not a default export. Use named import.

Shows how to reflect on a class: get property type, method return type, and check union types.

import 'reflect-metadata'; import { reflect } from 'typescript-rtti'; class User { id!: number; username?: string; protected favoriteColor?: number | string; doIt() { return 123; } } const reflectedUser = reflect(User); console.log('favoriteColor is union:', reflectedUser.getProperty('favoriteColor').type.is('union')); // true console.log('doIt return type is Number:', reflectedUser.getMethod('doIt').type.isClass(Number)); // true

Debug

Known issues

deprecatedThe reflect function signature may change in future stable versions.

fix

Pin to ^0.9.6 and watch changelog for breaking changes.

affects: <1.0

breakingTypeScript version must be exactly 4.8, 4.9, 5.0, or 5.1. Using other versions may cause build failures or incorrect metadata.

fix

Ensure TypeScript version matches one of the peer dependencies.

affects: >=0.9

gotchaMapped types (e.g., Partial<T>) are not supported and may produce no or incomplete metadata.

fix

Avoid using mapped types with reflect() or verify behavior per issue tracker.

affects: <=0.9.6

gotcharequire() style CommonJS imports may not work; the package is primarily ESM.

fix

Use import syntax. If using CommonJS, use dynamic import or ensure bundler configuration.

affects: >=0.8

Errors

Common errors & fixes

Error: reflect-metadata is not defined

reflect-metadata polyfill not imported before typescript-rtti.

fix

Add import 'reflect-metadata' at the top of your entry file.

Reflection metadata not emitted: no type data for class

TypeScript transformer is not configured or running.

fix

Add the typescript-rtti transformer to your tsconfig.json compilerOptions.plugins.

Argument of type 'typeof A' is not assignable to parameter of type 'ReflectableClass'

reflect() expects a class constructor, not an instance.

fix

Pass the class itself: reflect(A) not reflect(new A()).

Upgrade

Version history

0.9.6latest on npm

Audit

Dependencies

reflect-metadatarequiredrequired peer dependency for runtime metadata reflection

typescriptrequiredrequired peer dependency; transformer uses TypeScript compiler API

Agent activity

5 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/rezonant/typescript-rtti ↗

packagehttps://www.npmjs.com/package/typescript-rtti ↗