Modular API Client

This package offers a customizable API client using decorators, enabling the modification of request headers, addition of authentication, versioning, and more.

Installation

To install the package, you can use the following npm command:

npm install modular-api-client --save

Usage

Here's an example of how you might use the package in your code:

Basic Usage

Importing the Client

import {
  ApiClient,
  AxiosBaseApiClient,
  AxiosVersionDecorator,
  AxiosHeadersDecorator,
  AxiosDataDecorator,
} from 'modular-api-client';

Creating an Instance

const client = new ApiClient(new AxiosBaseApiClient('https://api.example.com'));

Adding Decorators

client.addDecorator({ decorator: AxiosVersionDecorator, params: { version: 'v1' } });
client.addDecorator({ decorator: AxiosHeadersDecorator, params: { 'X-Custom-Header': 'Custom Value' } });
client.addDecorator({ decorator: AxiosDataDecorator });

Making Requests

client.get({ url: '/users/1' }).then((response) => {
  console.log(response);
});

Result

request url: https://api.example.com/v1/users/1
request headers: { 'X-Custom-Header': 'Custom Value' }
response: { userId: 1, name: 'John Doe' }

Available Decorators

• AxiosVersionDecorator - adds a version to the request URL
• JWTRefreshDecorator - if the JWT token is expired, refreshes it and retries the request
• AxiosHeadersDecorator - adds custom headers to the request
• AxiosDataDecorator - receives only the data from the response
• RetryDecorator - retries the request if it fails

Advanced Usage

Creating Custom Decorators

Custom decorators allow you to extend the core functionality of the API client and encapsulate specific behavior related to logging, timing, authentication, headers, etc. By following the structure provided, you can create decorators that can be easily added or removed.

Implementing a Basic Custom Decorator

this example will apply the decorator to the GET method

// retry.decorator.js
import { Decorator } from 'modular-api-client';

export class RetryDecorator extends Decorator {
  constructor(apiClient, params) {
    super(apiClient);
    this.retries = params.retries;
    this.delay = params.delay;
  }

  get(options) {
    const attempt = async ({ retriesLeft }) => {
      try {
        return await this.apiClient.get(options);
      } catch (error) {
        if (retriesLeft > 0) {
          return new Promise((resolve) =>
            setTimeout(() => resolve(attempt({ retriesLeft: retriesLeft - 1 })), this.delay),
          );
        }
        return Promise.reject(error);
      }
    };

    return attempt({ retriesLeft: this.retries });
  }
}

// index.js
import { ApiClient, AxiosBaseApiClient } from 'modular-api-client';

const client = new ApiClient(new AxiosBaseApiClient('https://api.example.com'));
client.addDecorator({ decorator: RetryDecorator, params: { retries: 3, delay: 1000 } });
client.get({ url: '/users/1' }).then((response) => {
  console.log(response);
});

Implementing a Custom Decorator for all methods

this example will apply the decorator to all methods

export class RetryDecorator extends Decorator {
    // ...
    all(method, options) {
        const attempt = async ({ retriesLeft }) => {
        try {
            return await this.apiClient[method](options);
            // ...
        }
        // ...
        });
    // ...
    }
}

Applying Decorators to Specific Scope

'with' Method

The with method allows you to apply decorators to a specific scope.

Example

const client = new ApiClient(new AxiosBaseApiClient('https://api.example.com'));
clien.get({ url: '/users/1' });
// -> https://api.example.com/users/1

client.with({ decorator: AxiosVersionDecorator, params: { version: 'v1' } }).get({ url: '/users/1' });
// -> https://api.example.com/v1/users/1

client.get({ url: '/users/1' });
// -> https://api.example.com/users/1

'without' Method

The without method allows you to remove decorators from a specific scope.

Example

const client = new ApiClient(new AxiosBaseApiClient('https://api.example.com'));
client.addDecorator({ decorator: AxiosVersionDecorator, params: { version: 'v1' } });

client.get({ url: '/users/1' });
// -> https://api.example.com/v1/users/1

client.without({ decorator: AxiosVersionDecorator }).get({ url: '/users/1' });
// -> https://api.example.com/users/1

client.get({ url: '/users/1' });
// -> https://api.example.com/v1/users/1

Available Decorators API

AxiosVersionDecorator

Adds a version to the request URL.

Parameters

Name	Type	Description
version	string	The version to add to the request URL. The version is added as a prefix.

Example

client.addDecorator({ decorator: AxiosVersionDecorator, params: { version: 'v1' } });

---

JWTRefreshDecorator

If the JWT token is expired, refreshes it and retries the request.

Parameters

Name	Type	Description
refreshCallback	function	A function that returns a promise that resolves to a new JWT token.

Example

client.addDecorator({ decorator: JWTRefreshDecorator, params: { refreshCallback: <your-refresh-callback> } });

---

AxiosHeadersDecorator

Adds custom headers to the request.

Parameters

Name	Type	Description
	string	The name of the header to add to the request.

Example

client.addDecorator({ decorator: AxiosHeadersDecorator, params: { 'X-Custom-Header': 'Custom Value' } });

---

AxiosDataDecorator

Receives only the data from the response.

Parameters

None

Example

client.addDecorator({ decorator: AxiosDataDecorator });

---

RetryDecorator

Retries the request if it fails.

Parameters

Name	Type	Description
retries	number	The number of times to retry the request if it fails. The default is 3.
delay	number	The delay in milliseconds between each retry. The default is 1000 (1 sec).

Example

client.addDecorator({ decorator: RetryDecorator, params: { retries: 3, delay: 1000 } });