PlantUML Transpiler

1.0.0 verified Fri May 01 auth: no javascript

A Node.js library (v1.0.0, MIT) that converts PlantUML class diagrams into code for Java, C#, Python, Ruby, Kotlin, JavaScript, and TypeScript. Supports classes, interfaces, enums, abstract classes, generics, visibility modifiers, static/final members, and package/namespace handling. Key differentiators: multi-language output from a single PlantUML source, language-specific idioms, and type system mapping. Actively maintained with monthly releases.

Common errors

error TypeError: PlantUMLTranspiler is not a constructor ↓

cause Wrong import style; default export used as named export.

fix

Use 'import PlantUMLTranspiler from 'plantuml-transpiler'' or 'const { default: PlantUMLTranspiler } = require('plantuml-transpiler')'

error Unsupported target language: ruby (use java, csharp, python, ruby, kotlin, javascript, typescript) ↓

cause Language string mismatch; case-sensitive or unsupported language.

fix

Use lowercase language name: 'java', 'csharp', 'python', 'ruby', 'kotlin', 'javascript', or 'typescript'

error SyntaxError: Unexpected token (expected 'class', 'interface', 'enum', ...) ↓

cause Invalid PlantUML syntax in diagram.

fix

Ensure PlantUML starts with @startuml and ends with @enduml, and follows PlantUML class diagram syntax.

Warnings

gotcha PlantUML syntax must be valid; invalid diagrams produce errors. Use a parser or lint first. ↓

fix Validate PlantUML with a PlantUML parser before transpiling.

breaking v1.0.0 is the first stable release; API may change in minor versions before 2.0. ↓

fix Pin dependency to ^1.0.0 and test on upgrade.

deprecated CommonJS usage is deprecated; future versions may drop support. ↓

fix Switch to ES module imports: import PlantUMLTranspiler from 'plantuml-transpiler'

gotcha TypeScript source exports are type-only; runtime types not available in JavaScript. ↓

fix Use TypeScript or run tsc to generate declarations.

Install

npm install plantuml-transpiler

yarn add plantuml-transpiler

pnpm add plantuml-transpiler

Imports

PlantUMLTranspiler
wrong
```
const PlantUMLTranspiler = require('plantuml-transpiler')
```
correct
```
import PlantUMLTranspiler from 'plantuml-transpiler'
```
Default export; ESM import is preferred. CommonJS require works but is not officially recommended.
PlantUMLTranspiler
wrong
```
const PlantUMLTranspiler = require('plantuml-transpiler')
```
correct
```
const { default: PlantUMLTranspiler } = require('plantuml-transpiler')
```
For CommonJS with TypeScript or ESM-style import, use destructuring. Direct require may fail in some bundlers.

TranspilerOptions

wrong

import { TranspilerOptions } from 'plantuml-transpiler'

correct

import type { TranspilerOptions } from 'plantuml-transpiler'

TranspilerOptions is a TypeScript type only; use 'import type' in TS projects.

SupportedLanguage

wrong

import SupportedLanguage from 'plantuml-transpiler'

correct

import { SupportedLanguage } from 'plantuml-transpiler'

Named export, not default.

Quickstart

Creates a transpiler instance, parses a PlantUML class diagram with classes, interface, and relationships, then generates Java and TypeScript code.

import PlantUMLTranspiler from 'plantuml-transpiler';

const transpiler = new PlantUMLTranspiler();

const plantUmlCode = `
@startuml
class User {
  -id: int
  -name: String
  +User(id: int, name: String)
  +getId(): int
  +getName(): String
}

interface UserService {
  +findById(id: int): User
  +save(user: User): void
}

class UserServiceImpl {
  -userRepository: UserRepository
  +UserServiceImpl(userRepository: UserRepository)
  +findById(id: int): User
  +save(user: User): void
}

UserServiceImpl ..|> UserService
UserServiceImpl --> UserRepository
@enduml
`;

const javaCode = transpiler.transpile(plantUmlCode, 'java');
console.log(javaCode);

const tsCode = transpiler.transpile(plantUmlCode, 'typescript');
console.log(tsCode);