Resource Library

The Resource Library is a TypeScript utility that helps developers easily manage the transformation of data objects. It provides a customizable and flexible Resource class, allowing developers to define how data should be formatted before being sent to the client. This is similar to Laravel’s resource handling.

Installation

To install the Resource Library, use npm:

npm install resource.ts

or with Yarn:

yarn add resource.ts

Usage

Overview

The Resource class is designed to be extended in order to define specific data formats for different types of resources. When you create a subclass of Resource, you override the format method to specify how each item should be transformed. You can also use powerful filtering options, such as include and exclude, to dynamically manage which fields appear in the final JSON output.

Creating a Custom Resource

Let's go through the steps to create a custom resource. Suppose you have a Post type with several fields:

interface Post {
  id: number;
  title: string;
  author: string;
  content: string;
  createdAt: string;
  updatedAt: string;
}

Define a PostResource class extending Resource:

import { Resource } from 'resource-library';

interface ReturnPost {
  id: number;
  title: string;
  author: string;
  content: string;
}

class PostResource extends Resource<Post, ReturnPost> {
  protected format(item: Post): ReturnPost {
    return {
      id: item.id,
      title: item.title,
      author: item.author,
      content: item.content,
    };
  }
}

Using toJSON with Filtering

You can call the toJSON method on the PostResource instance to output a JSON-friendly version of the data. You can use include or exclude to control which fields are included or excluded in the output.

const posts: Post[] = [
  {
    id: 1,
    title: 'First Post',
    author: 'John',
    content: 'This is the first post',
    createdAt: '2024-01-01',
    updatedAt: '2024-01-01',
  },
  {
    id: 2,
    title: 'Second Post',
    author: 'Jane',
    content: 'This is the second post',
    createdAt: '2024-01-02',
    updatedAt: '2024-01-02',
  },
];

const postResource = new PostResource(posts);
const output = postResource.toJSON(['id', 'title']);
console.log(output);

API Reference

new Resource(data)

Creates a new instance of the Resource class with the provided data. This data can be either a single object or an array of objects.

• data: T | T[] — The data to be transformed by the resource.

toJSON(fields?: string[], exclude?: boolean)

Converts the resource's data to a JSON-compatible format, optionally including or excluding specified fields.

• fields: string[] (optional) — An array of field names to include or exclude in the output.
• exclude: boolean (optional) — If true, treat fields as fields to exclude instead.

Example Usage with Filtering

In the example below, we’ll use both include and exclude options to control which fields appear in the final output:

// Exclude specific fields
const outputExclude = postResource.toJSON(['createdAt', 'updatedAt'], true);
console.log(outputExclude);

// Include specific fields only
const outputInclude = postResource.toJSON(['id', 'author']);
console.log(outputInclude);

License

This project is licensed under the MIT License.