# useFetchUrl

A custom hooks in TypeScript for fetching data from a URL and managing its state, including status and error information.


# API Reference

## `useFetchUrl` Hook in Typescript

Hook that makes the request itself

### Parameters
```typescript
useFetchUrl<T, K = unknown>(url: string, initialValue: T) => AnswerInterface<T, K>
```
| Parameters | Type     | Description                       |
| :-------- | :------- | :-------------------------------- |
| `url`      | `string` | **Required**. URL to fetch data from |
| `initialValue` | `T` | Initial value of data (optional with default `null`) |
| `T` | any type | Type of data |
| `K` | `unknown` or any type | Type of error (optional with default `unknown`) |

### Usage

Call the hook `useFetchUrl` with two generic parameters, `T` and `K`, representing the type of data to be fetched and the type of error, respectively. The second generic parameter is optional and has a default of `unknown`.

Pass in two arguments: the URL to fetch data from and an initial value for the data (optional with default `null`).

Example:

```typescript
import { useFetchUrl } from "./useFetchUrl";
import { FetchStatus } from "./FetchStatus";

interface IData {
  message: string;
}

interface IError {
  message: string
}

const initialValue: IData = { message: "Important things!" };

const App = () => {
  const { data, status, error } = useFetchUrl<IData, IError>("https://your-url", initialValue);

  if (status === FetchStatus.LOADING) {
    return <div>Loading...</div>;
  }

  if (status === FetchStatus.ERROR) {
    return <div>{error}</div>;
  }

  return <div>{data.message}</div>;
};
```

### Return type

The hook returns an object with three properties:

* `data`: state of data of type T
* `status`: status of fetch operation of type FetchStatus
* `error`: error message of type K (if any)

## `useFetch` Hook in TypeScript

Hook using a passed promise

### Parameters
```typescript
useFetch<T, K = unknown>(PromiseFunction: () => Promise<T>, initialValue: T) => AnswerInterface<T, K>
```
| Parameters | Type     | Description                       |
| :-------- | :------- | :-------------------------------- |
| `PromiseFunction`      | `() => Promise<T>` | **Required**. Promise function to fetch data from |
| `initialValue` | `T` | Initial value of data (optional with default `null`) |
| `T` | any type | Type of data |
| `K` | `unknown` or any type | Type of error (optional with default `unknown`) |

### Usage

Call the hook `useFetch` with two generic parameters, `T` and `K`, representing the type of data to be fetched and the type of error, respectively. The second generic parameter is optional and has a default of `unknown`.

Pass in two arguments: the Promise function to fetch data from and an initial value for the data (optional with default `null`).

Example:

```typescript
import { useFetch } from "./useFetch";
import { FetchStatus } from "./FetchStatus";

interface IData {
  message: string;
}

interface IError {
  message: string
}

const initialValue: IData = { message: "" };

const fetchData = () => {
  return new Promise<Data>(resolve => {
    setTimeout(() => {
      resolve({ message: "Important things!" });
    }, 1000);
  });
};

const App = () => {
  const { data, status, error } = useFetch<IData, string>(fetchData, initialValue);

  if (status === FetchStatus.LOADING) {
    return <div>Loading...</div>;
  }

  if (status === FetchStatus.ERROR) {
    return <div>{error}</div>;
  }

  return <div>{data.message}</div>;
};
```

### Return type

The hook returns an object with three properties:

* `data`: state of data of type T
* `status`: status of fetch operation of type FetchStatus
* `error`: error message of type K (if any)

## `FetchStatus` Enum

This is a TypeScript enum that consists of three fields: `COMPLETE`, `LOADING`, and `ERROR`. It represents the status of a fetch operation.

```typescript
enum FetchStatus {
  COMPLETE,
  LOADING,
  ERROR
}
```

## `AnswerFetch` Type

A type in TypeScript that describes the possible states of a fetch operation, including complete, loading, and error states.

### Usage

This type is used to describe the shape of an object returned from a fetch operation, with three possible states: `CompleteFetch`, `LoadingFetch`, and `ErrorFetch`.

### Types

| Type                   | Description                                                                            |
|-----------------------|----------------------------------------------------------------------------------------|
| `CompleteFetch<T>`    | Represents a successful fetch operation with data of type `T`. Includes:<br>- `status` of `FetchStatus.COMPLETE`<br>- `data` of type `T`<br>- `error` of `null`. |
| `LoadingFetch`        | Represents a fetch operation in progress with:<br>- `status` of `FetchStatus.LOADING`<br>- `data` of `null`<br>- `error` of `null`. |
| `ErrorFetch<K>`       | Represents a failed fetch operation with:<br>- `status` of `FetchStatus.ERROR`<br>- `data` of `null`<br>- `K` as the type of error. |
| `AnswerFetch<T, K>`  | Represents any of the three fetch states, with:<br>- `T` as the type of successful data<br>- `K` as the type of error. |


# Advanced usage
You can create a wrapper for the hook to useFetchUrl even more cleanly.

This is the `useUsers` file.
```typescript
interface IUser {
    name: string,
    age: number
}

//You can do the same using the useFetch hook
export const useUsers = () => useFetchUrl<IUser[]>("https://your-url/users")
```

This is the `Users` file.

```typescript
import { useUsers } from "./hooks/useUsers";

const Users = () => {
  const { data, status, error } = useUsers();
  const {COMPLETE, ERROR, LOADING} = FetchStatus

  if (status === LOADING) 
    return <div>Loading...</div>;
  if (status === ERROR) 
    return <div>{error}</div>;
  if (status === COMPLETE)
  return (
      <div>
        {data.map(user => 
            <div>
                {user.name} - {user.age}
            </div>
        )}
      </div>
  );
};
```