Fast, lightweight and reusable data fetching

Why?

Managing multiple API endpoints can be complex and time-consuming. fetchff simplifies this process by offering a straightforward, declarative approach to API handling using Repository Pattern. It reduces the need for extensive setup and middlewares, allowing developers to focus on data manipulation and application logic.

Key Benefits:

✅ Simplicity: Minimal code footprint for managing extensive APIs.

✅ Productivity: Streamlines API interactions, enhancing developer efficiency.

✅ Scalability: Easily scales from a few endpoints to complex API networks.

Features

• 100% Performance-Oriented: Optimized for speed and efficiency, ensuring fast and reliable API interactions.
• Fully TypeScript Compatible: Enjoy full TypeScript support for better development experience and type safety.
• Smart Error Retry: Features exponential backoff for intelligent error handling and retry mechanisms.
• Automatic Request Deduplication: Set the time during which requests are deduplicated (treated as same request).
• Dynamic URLs Support: Easily manage routes with dynamic parameters, such as /user/:userId.
• Native fetch() Support: Uses the modern fetch() API by default, eliminating the need for libraries like Axios.
• Global and Per Request Error Handling: Flexible error management at both global and individual request levels.
• Automatic Request Cancellation: Utilizes AbortController to cancel previous requests automatically.
• Global and Per Request Timeouts: Set timeouts globally or per request to prevent hanging operations.
• Multiple Fetching Strategies: Handle failed requests with various strategies - promise rejection, silent hang, soft fail, or default response.
• Multiple Requests Chaining: Easily chain multiple requests using promises for complex API interactions.
• Supports All Axios Options: Fully compatible with all Axios configuration options for seamless integration.
• Lightweight: Minimal footprint, only a few KBs when gzipped, ensuring quick load times.
• Framework Independent: Pure JavaScript solution, compatible with any framework or library.
• Browser and Node 18+ Compatible: Works flawlessly in both modern browsers and Node.js environments.
• Custom Interceptors: Includes onRequest, onResponse, and onError interceptors for flexible request and response handling.

Please open an issue for future requests.

✔️ Quick Start

Using NPM:

npm install fetchff

Using Pnpm:

pnpm install fetchff

Using Yarn:

yarn add fetchff

Standalone usage

import { fetchf } from 'fetchff';

const { data, error, status } = await fetchf('/api/user-details');

Multiple API Endpoints

import { createApiFetcher } from 'fetchff';

const api = createApiFetcher({
  apiUrl: 'https://example.com/api',
  strategy: 'softFail', // no try/catch required
  // Other global settings...
  endpoints: {
    getUser: {
      method: 'get',
      url: '/user-details',
      // All global settings can be added per endpoint...
    },
  },
});

// GET request to http://example.com/api/user-details?userId=1
const { data } = await api.getUser({ userId: 1 });

// GET request to http://example.com/api/user-details?userId=2&ratings[]=1&ratings[]=2
const { data, error, status } = await api.getUser({
  userId: 2,
  ratings: [1, 2],
});

✔️ Easy Integration with React and Other Libraries

fetchff is designed to seamlessly integrate with any popular libraries like React, Vue, React Query and SWR. It is written in pure JS so you can effortlessly manage API requests with minimal setup, and without any dependencies.

🌊 Using with React

You can implement a useApi() hook to handle the data fetching. Since this package has everything included, you don't really need anything more than a simple hook to utilize.

import { createApiFetcher } from 'fetchff';

const api = createApiFetcher({
  apiUrl: 'https://example.com/api',
  strategy: 'softFail',
  endpoints: {
    getProfile: {
      url: '/profile/:id',
    },
  },
});

export const useApi = (apiFunction) => {
  const [data, setData] = useState(null);
  const [error,] = useState(null);
  const [isLoading, setLoading] = useState(true);

  useEffect(() => {
    const fetchData = async () => {
      setLoading(true);

      const { data, error } = await apiFunction();

      if (error) {
          setError(error);
      } else {
          setData(data);
      }

      setLoading(false);
    };

    fetchData();
  }, [apiFunction]);

  return {data, error, isLoading, setData};
};

const ProfileComponent = ({ id }) => {
  const { data: profile, error, isLoading } = useApi(() => api.getProfile({ id }));

  if (isLoading) return <div>Loading...</div>;
  if (error) return <div>Error: {error.message}</div>;

  return <div>{JSON.stringify(profile)}</div>;
};

Using with React Query

Integrate fetchff with React Query to streamline your data fetching:

import { createApiFetcher } from 'fetchff';

const api = createApiFetcher({
  apiUrl: 'https://example.com/api',
  endpoints: {
    getProfile: {
      url: '/profile/:id',
    },
  },
});

export const useProfile = ({ id }) => {
  return useQuery(['profile', id], () => api.getProfile({ id }));
};

Using with SWR

Combine fetchff with SWR for efficient data fetching and caching:

import { createApiFetcher } from 'fetchff';
import useSWR from 'swr';

const api = createApiFetcher({
  apiUrl: 'https://example.com/api',
  endpoints: {
    getProfile: {
      url: '/profile/:id',
    },
  },
});

export const useProfile = ({ id }) => {
  const fetcher = () => api.getProfile({ id });

  const { data, error } = useSWR(['profile', id], fetcher);

  return {
    profile: data,
    isLoading: !error && !data,
    isError: error,
  };
};

Check examples below for more integrations with other libraries.

✔️ API

fetchf()

fetchf() is a functional wrapper for fetch(). It integrates seamlessly with the retry mechanism and error handling improvements. Unlike the traditional class-based approach, fetchf() can be used directly as a function, simplifying the usage and making it easier to integrate with functional programming styles.

import { fetchf } from 'fetchff';

const { data, error } = await fetchf('/api/user-details', {
  timeout: 5000,
  cancellable: true,
  retry: { retries: 3, delay: 2000 },
  // All other fetch() settings work as well...
});

The fetchf() makes requests independently from createApiFetcher()

Challenges with Native Fetch:

• Error Status Handling: Fetch does not throw errors for HTTP error statuses, making it difficult to distinguish between successful and failed requests based on status codes alone.
• Error Visibility: Error responses with status codes like 404 or 500 are not automatically propagated as exceptions, which can lead to inconsistent error handling.

To address these challenges, the fetchf() provides several enhancements:

1. Consistent Error Handling:

   • In JavaScript, the native fetch() function does not reject the Promise for HTTP error statuses such as 404 (Not Found) or 500 (Internal Server Error). Instead, fetch() resolves the Promise with a Response object, where the ok property indicates the success of the request. If the request encounters a network error or fails due to other issues (e.g., server downtime), fetch() will reject the Promise.
   • This approach aligns error handling with common practices and makes it easier to manage errors consistently.

2. Enhanced Retry Mechanism:

   • Retry Configuration: You can configure the number of retries, delay between retries, and exponential backoff for failed requests. This helps to handle transient errors effectively.
   • Custom Retry Logic: The shouldRetry asynchronous function allows for custom retry logic based on the error and attempt count, providing flexibility to handle different types of failures.
   • Retry Conditions: Errors are only retried based on configurable retry conditions, such as specific HTTP status codes or error types.

3. Improved Error Visibility:

   • Error Wrapping: The createApiFetcher() and fetchf() wrap errors in a custom RequestError class, which provides detailed information about the request and response, similarly to what Axios does. This makes debugging easier and improves visibility into what went wrong.

4. Extended settings:

   • Check Settings table for more information about all settings.

createApiFetcher()

createApiFetcher() is a powerful factory function for creating API fetchers with advanced features. It provides a convenient way to configure and manage multiple API endpoints using a declarative approach. This function offers integration with retry mechanisms, error handling improvements, and other advanced configurations. Unlike traditional methods, createApiFetcher() allows you to set up and use API endpoints efficiently with minimal boilerplate code.

Usage Example

import { createApiFetcher } from 'fetchff';

const api = createApiFetcher({
  apiUrl: 'https://example.com/api',
  endpoints: {
    getUserDetails: {
      url: '/user-details',
      method: 'GET',
      retry: { retries: 3, delay: 2000 },
      timeout: 5000,
      cancellable: true,
      strategy: 'softFail',
    },
    updateUser: {
      url: '/update-user',
      method: 'POST',
      retry: { retries: 2, delay: 1000 },
    },
    // Define more endpoints as needed
  },
});

// Example usage
const { data, error } = await api.getUserDetails();

The const api methods and properties are described below:

api.myEndpointName(queryParams, urlPathParams, requestConfig)

Where "myEndpointName" is the name of your endpoint from endpoints object passed to the createApiFetcher().

queryParams / bodyPayload (optional) - Query Parameters or Body Payload for POST requests.

The first argument of API functions is an object that can serve different purposes based on the type of request being made:

• For GET and HEAD Requests: This object will be treated as query parameters. You can pass key-value pairs where the values can be strings, numbers, or arrays. For example, if you pass { foo: [1, 2] }, it will be automatically serialized into foo[]=1&foo[]=2 in the URL.

• For POST (and similar) Requests: This object is used as the data payload. It will be sent in the body of the request. If your request also requires query parameters, you can still pass those in the first argument and then use the requestConfig.body or requestConfig.data for the payload.

Note: If you need to use Query Params in the POST (and similar) requests, you can pass them in this argument and then use body or data in requestConfig (third argument).

urlPathParams (optional) - Dynamic URL Path Parameters

The urlPathParams option allows you to dynamically replace parts of your URL with specific values in a declarative and straightforward way. This feature is particularly useful when you need to construct URLs that include variables or identifiers within the path.

For example, consider the following URL template: /user-details/update/:userId. By using urlPathParams, you can easily replace :userId with an actual value when the API request is made.

requestConfig (optional) - Request Configuration to overwrite global config in case To have more granular control over specific endpoints you can pass Request Config for particular endpoint. See the Settings below for more information.

Returns: response or data object, depending on flattenResponse setting.

Response Object without flattenResponse (default)

When flattenResponse is disabled, the response object includes a more detailed structure, encapsulating various aspects of the response:

• data:

  • Contains the actual data returned from the API request.

• error:

  • An object with details about any error that occurred or null otherwise.
  • name: The name of the error (e.g., 'ResponseError').
  • message: A descriptive message about the error.
  • status: The HTTP status code of the response (e.g., 404, 500).
  • statusText: The HTTP status text of the response (e.g., 'Not Found', 'Internal Server Error').
  • request: Details about the HTTP request that was sent (e.g., URL, method, headers).
  • config: The configuration object used for the request, including URL, method, headers, and query parameters.
  • response: The full response object received from the server, including all headers and body.

• config:

  • The configuration object with all settings used for the request, including URL, method, headers, and query parameters.

• request:

  • An alias for config.

• headers:

  • The response headers returned by the server, such as content type and caching information returned as simple key-value object.

Response Object with flattenResponse

When the flattenResponse option is enabled, the data from the API response is directly exposed as the top-level property of the response object. This simplifies access to the actual data, as it is not nested within additional response metadata.

Key Points

• With flattenResponse Enabled:

  • data: Directly contains the API response data.

• With flattenResponse Disabled:

  • data: Contains the API response data nested within a broader response structure.
  • error: Provides detailed information about any errors encountered.
  • config: Shows the request configuration.
  • request: Details the actual HTTP request sent.
  • headers: Includes the response headers from the server.

The flattenResponse option provides a more streamlined response object by placing the data directly at the top level, while disabling it gives a more comprehensive response structure with additional metadata.

api.config

You can access api.config property directly, so to modify global headers, and other settings on fly. Please mind it is a property, not a function.

api.endpoints

You can access api.endpoints property directly, so to modify endpoints list. It can be useful if you want to append or remove global endpoints. Please mind it is a property, not a function.

api.getInstance()

When API handler is firstly initialized, a new custom fetcher instance is created. You can call api.getInstance() if you want to get that instance directly, for example to add some interceptors. The instance of fetcher is created using fetcher.create() functions. Your fetcher can include anything. It will be triggered instead of native fetch() that is available by default.

api.request()

The api.request() helper function is a versatile method provided for making API requests with customizable configurations. It allows you to perform HTTP requests to any endpoint defined in your API setup and provides a straightforward way to handle queries, path parameters, and request configurations dynamically.

Example

import { createApiFetcher } from 'fetchff';

const api = createApiFetcher({
  apiUrl: 'https://example.com/api',
  endpoints: {
    getUserDetails: {
      url: '/user-details/:id',
      method: 'GET',
    },
    updateUser: {
      url: '/update-user',
      method: 'POST',
    },
    // Define more endpoints as needed
  },
});

// Using api.request to make a GET request
const { data, error } = await api.request(
  'getUserDetails',
  null, // no Query Params passed
  {
    id: '123', // URL Path Param :id
  },
);

// Using api.request to make a POST request
const { data, error } = await api.request('updateUser', {
  name: 'John Doe', // Data Payload
});

// Using api.request to make a GET request to an external API
const { data, error } = await api.request('https://example.com/api/user', {
  name: 'John Smith', // Query Params
});

✔️ Settings (Request Config)

Global settings are passed to createApiFetcher() function. Settings that are global only are market with star * next to setting name.

Almost all settings can be passed on per-request basis in the third argument of endpoint function, for example api.getUser({}, {}, { /* Request Config */ }).

You can also pass all fetch() settings.

| Setting | Type | Default | Description | | ------------------ | ------------------ | ---------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | apiUrl * | string | | Your API base url. | | endpoints * | object | | List of your endpoints. Each endpoint accepts all these settings. They can be set globally or per-endpoint when they are called. | | fetcher * | Function | fetch | The native fetch() is used by default. A custom instance that exposes create() and request() can be used otherwise. | | strategy | string | reject | Error handling strategies - basically what to return when an error occurs. It can be a default data, promise can be hanged (nothing would be returned) or rejected so to use try/catch.Available: reject, softFail, defaultResponse, silent.reject - Promises are rejected, and global error handling is triggered. Requires try/catch for handling.softFail - returns a response object with additional properties such as data, error, config, request, and headers when an error occurs. This approach avoids throwing errors, allowing you to handle error information directly within the response object without the need for try/catch blocks.defaultResponse - returns default response specified in case of an error. Promise will not be rejected. It could be used in conjuction with flattenResponse and as defaultResponse: {} so to provide a sensible defaults.silent - hangs the promise silently on error, useful for fire-and-forget requests without the need for try/catch. In case of an error, the promise will never be resolved or rejected, and any code after will never be executed. The requests could be dispatched within an asynchronous wrapper functions that do not need to be awaited. If used properly, it prevents excessive usage of try/catch or additional response data checks everywhere. You can use it in combination with onError to handle errors separately. | | cancellable | boolean | false | If true, any ongoing previous requests to same API endpoint will be cancelled, if a subsequent request is made meanwhile. This helps you avoid unnecessary requests to the backend. | | rejectCancelled | boolean | false | If true and request is set to cancellable, a cancelled requests' promise will be rejected. By default, instead of rejecting the promise, defaultResponse is returned. | | flattenResponse | boolean | false | Flatten nested response data, so you can avoid writing response.data.data and obtain response directly. Response is flattened when there is a "data" within response "data", and no other object properties set. | | defaultResponse | any | null | Default response when there is no data or when endpoint fails depending on the chosen strategy | | withCredentials | boolean | false | Indicates whether credentials (such as cookies) should be included with the request. | | timeout | int | 30000 | You can set a request timeout for all requests or particular in milliseconds. | | dedupeTime | int | 1000 | Time window, in milliseconds, during which identical requests are deduplicated (treated as single request). | | onRequest | function(config) | | You can specify a function that will be triggered before the request is sent. The request configuration object will be sent as the first argument of the function. This is useful for modifying request parameters, headers, etc. | | onResponse | function(response) | | You can specify a function that will be triggered when the endpoint successfully responds. The full Response Object is sent as the first argument of the function. This is useful for handling the response data, parsing, and error handling based on status codes. | | onError | function(error) | | You can specify a function or class that will be triggered when endpoint fails. If it's a class it should expose a process method. When using native fetch(), the full Response Object is sent as a first argument of the function. | | logger | object | null | You can additionally specify logger object with your custom logger to automatically log the errors to the console. It should contain at least error and warn functions. | | url | string | | URL path e.g. /user-details/get | | method | string | get | Default request method e.g. GET, POST, DELETE, PUT etc. | | urlPathParams | object | {} | An object representing URL path parameters. These parameters are used to dynamically replace placeholders in the URL path. For example, if your URL contains a placeholder like /users/:userId, you can provide an object with the userId key to replace that placeholder with an actual value. The keys in the urlPathParams object should match the placeholders in the URL. This allows for dynamic URL construction based on runtime values. | | retry | object | | The object with retry settings available below. | | retry.retries | number | 0 | The number of times to retry the request in case of failure. If set to 0 (default), no retries will be attempted. | | retry.delay | number | 1000 | The initial delay (in milliseconds) between retry attempts. | | retry.backoff | number | 1.5 | The backoff factor to apply to the delay between retries. For example, if the delay is 100ms and the backoff is 1.5, the next delay will be 150ms, then 225ms, and so on. | | retry.maxDelay | number | 30000 | The maximum delay (in milliseconds) between retry attempts. | | retry.resetTimeout | boolean | true | Reset timeout when retrying requests. | | retry.retryOn | array | [408, 409, 425, 429, 500, 502, 503, 504] | An array of HTTP status codes on which to retry the request. Default values include: 408 (Request Timeout), 409 (Conflict), 425 (Too Early), 429 (Too Many Requests), 500 (Internal Server Error), 502 (Bad Gateway), 503 (Service Unavailable), 504 (Gateway Timeout). | | retry.shouldRetry | async function | | A custom asynchronous function to determine whether to retry the request. It receives two arguments: error (the error object) and attempts (the number of attempts made so far). |

✔️ Retry Mechanism

The exposed fetchf() and createApiFetcher() functions include a built-in retry mechanism to handle transient errors and improve the reliability of network requests. This mechanism automatically retries requests when certain conditions are met, providing robustness in the face of temporary failures. Below is an overview of how the retry mechanism works and how it can be configured.

Configuration

The retry mechanism is configured via the retry option when instantiating the RequestHandler. You can customize the following parameters:

• retries: Number of retry attempts to make after an initial failure. Default is 0 which means not to retry any requests.

• delay: Initial delay (in milliseconds) before the first retry attempt. Subsequent retries use an exponentially increasing delay based on the backoff parameter. Default is 1000.

• maxDelay: Maximum delay (in milliseconds) between retry attempts. The delay will not exceed this value, even if the exponential backoff would suggest a longer delay. Default is 30000.

• backoff: Factor by which the delay is multiplied after each retry. For example, a backoff factor of 1.5 means each retry delay is 1.5 times the previous delay. Default is 1.5.

• retryOn: Array of HTTP status codes that should trigger a retry. By default, retries are triggered for the following status codes:

  • 408 - Request Timeout
  • 409 - Conflict
  • 425 - Too Early
  • 429 - Too Many Requests
  • 500 - Internal Server Error
  • 502 - Bad Gateway
  • 503 - Service Unavailable
  • 504 - Gateway Timeout

• shouldRetry(error, attempts): Function that determines whether a retry should be attempted based on the error and the current attempt number. This function receives the error object and the attempt number as arguments.

How It Works

1. Initial Request: When a request fails, the retry mechanism captures the failure and checks if it should retry based on the retryOn configuration and the result of the shouldRetry function.

2. Retry Attempts: If a retry is warranted:

   • The request is retried up to the specified number of attempts (retries).
   • Each retry waits for a delay before making the next attempt. The delay starts at the initial delay value and increases exponentially based on the backoff factor, but will not exceed the maxDelay.

3. Logging: During retries, the mechanism logs warnings indicating the retry attempts and the delay before the next attempt, which helps in debugging and understanding the retry behavior.

4. Final Outcome: If all retry attempts fail, the request will throw an error, and the final failure is processed according to the configured error handling logic.

Check Examples section below for more information.

Comparison with another libraries

| Feature | fetchff | ofetch | wretch | axios | native fetch() | | --------------------------------------- | ------------ | ------------ | ------------ | ------------ | -------------- | | Unified API Client | ✅ | -- | -- | -- | -- | | Automatic Request Deduplication | ✅ | -- | -- | -- | -- | | Customizable Error Handling | ✅ | -- | ✅ | ✅ | -- | | Retries with exponential backoff | ✅ | -- | -- | -- | -- | | Custokm Retry logic | ✅ | ✅ | ✅ | -- | -- | | Easy Timeouts | ✅ | ✅ | ✅ | ✅ | -- | | Easy Cancellation | ✅ | -- | -- | -- | -- | | Default Responses | ✅ | -- | -- | -- | -- | | Global Configuration | ✅ | -- | ✅ | ✅ | -- | | TypeScript Support | ✅ | ✅ | ✅ | ✅ | ✅ | | Interceptors | ✅ | ✅ | ✅ | ✅ | -- | | Request and Response Transformation | ✅ | ✅ | ✅ | ✅ | -- | | Integration with Libraries | ✅ | ✅ | ✅ | ✅ | -- | | Request Queuing | ✅ | -- | -- | -- | -- | | Multiple Fetching Strategies | ✅ | -- | -- | -- | -- | | Dynamic URLs | ✅ | -- | ✅ | -- | -- | | Automatic Retry on Failure | ✅ | ✅ | -- | ✅ | -- | | Server-Side Rendering (SSR) Support | ✅ | ✅ | -- | -- | -- | | Minimal Installation Size | 🟢 (2.83 KB) | 🟡 (6.51 KB) | 🟢 (2.16 KB) | 🔴 (13.9 KB) | 🟢 (0 KB) | | Built-in AbortController Support | ✅ | -- | -- | -- | -- |

Please mind that this table is for informational purposes only. All of these solutions differ. For example swr and react-query are more focused on React, re-rendering, query caching and keeping data in sync, while fetch wrappers like fetchff