ts-derive

The "Derive" pattern with TypeScript decorators.

Overview

ts-derive is a TypeScript library inspired by Rust's powerful derive attribute. Just as Rust's derive allows developers to automatically implement traits for their types based on simple annotations, ts-derive enables developers to implement interfaces for their TypeScript classes based on simple annotations.

The primary goal of ts-derive is to shift the focus from manually implementing boilerplate logic to declaring what the code represents and what capabilities it should have. By leveraging these declarations (applied via decorators), the library can automate the generation of significant portions of the application's components, reducing manual coding effort and potential errors.

A key capability enabled by ts-derive is the ability to use the source code itself as a rich knowledge base. Through code introspection and the metadata provided by decorators, ts-derive can extract structured information. This knowledge can be represented and processed, potentially enabling advanced use cases such as:

• Automated Code Generation: Generating serialization/deserialization logic, API endpoints, documentation, configuration files, etc., based on class structure and decorators.
• Knowledge Representation: Representing code structure and relationships as structured data, potentially in formats like triples (subject, predicate, object).
• Rule-Based Reasoning: Inferring implicit knowledge or verifying constraints based on the declared metadata.

By providing an abstraction layer for annotations and powerful introspection capabilities, ts-derive empowers developers to precisely build robust, predictable programs with substantially decreased manual effort and maintenance costs.

Example

The following example illustrates how to derive the TypeScript class declaration of a class using ts-morph.

import { assertEquals } from "@std/assert/equals";
import { derive, getDerivedValue } from "../../derive.ts";
import { FilePath } from "../file-path/file-path.ts";
import type { ClassDeclaration } from "./typescript.ts";
import { classDeclaration } from "./auto.ts";

const filePath = FilePath.fromMeta(import.meta);

@derive(filePath, classDeclaration)
class Person {}

Deno.test({
  name: "Derive ClassDeclaration example (auto)",
  fn: () => {
    const actual = getDerivedValue<ClassDeclaration>(Person);
    assertEquals(actual.classDeclaration.name, "Person");
  },
});

Develop

Run unit tests.

deno task test

Format code.

deno fmt

Lint code.

deno lint

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