### Installing Fortnox API Client - npm

Source: https://github.com/rantalainen/fortnox-api-client/blob/main/README.md

Installs the @rantalainen/fortnox-api-client package using the npm package manager.

```shell
npm install @rantalainen/fortnox-api-client
```

--------------------------------

### Importing FortnoxApiClient - JavaScript

Source: https://github.com/rantalainen/fortnox-api-client/blob/main/README.md

Imports the FortnoxApiClient class from the installed package into a JavaScript or TypeScript file.

```javascript
import { FortnoxApiClient } from '@rantalainen/fortnox-api-client';
```

--------------------------------

### Initializing FortnoxApiClient - JavaScript

Source: https://github.com/rantalainen/fortnox-api-client/blob/main/README.md

Creates a new instance of the FortnoxApiClient, configuring it with client credentials and either an access token or a refresh token for API access.

```javascript
const fortnox = new FortnoxApiClient({
  clientId: 'your client id',
  clientSecret: 'your client secret',

  // To use endpoints you need to provide either accessToken or refreshToken to the client
  // If refreshToken is provided, the accessToken will be acquired on first request and refreshToken will also refresh
  // To acquire these tokens see above information about authentication/authorization
  accessToken: 'token for Fortnox API',
  refreshToken: 'token for Fortnox API'
});
```

--------------------------------

### Fetching Company Information - JavaScript

Source: https://github.com/rantalainen/fortnox-api-client/blob/main/README.md

Demonstrates how to use the initialized FortnoxApiClient instance to call an API endpoint, specifically fetching company information.

```javascript
const company = await fortnox.api.companyinformation.getCompanyInformationResource();

console.log(company);
```

--------------------------------

### Generating Fortnox Authorization URI - JavaScript

Source: https://github.com/rantalainen/fortnox-api-client/blob/main/README.md

Uses the static createAuthorizationUri method to generate the URL for initiating the Fortnox authorization flow. Requires client ID, redirect URI, scope, state, and type.

```javascript
const authorizationUri = FortnoxApiClient.createAuthorizationUri(
  'your client id',
  'your integration redirect uri',

  // required scope
  ['companyinformation'],

  // state that should match while getting tokens in the next step
  'state',

  // type of authorization
  'service'
);
```

--------------------------------

### Fetching Fortnox Tokens by Authorization Code - JavaScript

Source: https://github.com/rantalainen/fortnox-api-client/blob/main/README.md

Retrieves access and refresh tokens from Fortnox using the authorization code obtained from the authorization flow. Requires client ID, client secret, redirect URI, and the authorization code.

```javascript
// Authorization Code acquired from previous step
const code = 'xxxx';

// State acquired from previous step
const state = 'xxxx';

// Validate state
if (state !== expectedState) {
  // Something wrong with authorization
}

const tokens = await FortnoxApiClient.getTokensByAuthorizationCode(
  'your client id',
  'your client secret',
  'your integration redirect uri',
  code
);

// tokens.accessToken = 1hour token to use Fortnox API
// tokens.refreshToken = 45day long lived token to refresh access token when necessary
```

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