LZLD (Pronounced 'lazy load') 🦥

0 Dependency code splitting, lazy loading, and active code generation without transpilers for Typescript and NodeJS backends.

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Install

npm install lzld

TLDR;

Lazy Loading (for an HTTP API)

1. Define a base class all your entrypoints will extend (Plain Old Javascript Class)

export class APIHandler {
  static http: {
    method: 'POST' | 'PUT' | 'GET'
    path: string
  }

  async handle(): Promise<unknown> {
    throw new Error('Not implemented')
  }
}

2. Define an entrypoint with that base class

const myHandlers = Entrypoint.init(APIHandler, {
  __filename,
  metadataFilepath: './metadata/handlers.generated.json',
  match: /([a-zA-Z0-9]+).handler.ts$/,
  getMetadata: (target, { result: [, name] }) => ({
    name,
    path: target.http.path,
    method: target.http.method,
  }),
});

3. Write a bunch of handlers in any nested path like ./features/api/users/GetUser.handler.ts that implement your base class

4. Lazy load a handler with express routing or anything that returns a boolean

const Handler = myHandlers.find(({ path }) => matchPath(path, somePassedPath))

Code Generation

Generate some random .yaml file for serverless/ansible/etc with template literal syntax

myHandlers.codegen('./all_routes.yaml')
`routes:
${({entries}) => entries.map(({ meta }) => `${meta.name}: '${meta.method} ${method.path}'`)}
`

Generates ./all_routes.yaml:

routes:
  GetUsers: 'GET /users/:userId'
  GeneratePDF: 'POST /pdf/generate'

...

Read the Docs