# pkce-challenge
Generate or verify a Proof Key for Code Exchange (PKCE) challenge pair.
Read more about [PKCE](https://www.oauth.com/oauth2-servers/pkce/authorization-request/).
## Installation
```bash
npm install pkce-challenge
```
## Usage
Default length for the verifier is 43
```js
import pkceChallenge from "pkce-challenge";
await pkceChallenge();
```
gives something like:
```js
{
code_verifier: 'u1ta-MQ0e7TcpHjgz33M2DcBnOQu~aMGxuiZt0QMD1C',
code_challenge: 'CUZX5qE8Wvye6kS_SasIsa8MMxacJftmWdsIA_iKp3I'
}
```
### Specify a verifier length
```js
const challenge = await pkceChallenge(128);
challenge.code_verifier.length === 128; // true
```
### Challenge verification
```js
import { verifyChallenge } from "pkce-challenge";
(await verifyChallenge(challenge.code_verifier, challenge.code_challenge)) ===
true; // true
```
### Challenge generation from existing code verifier
```js
import { generateChallenge } from "pkce-challenge";
(await generateChallenge(challenge.code_verifier)) === challenge.code_challenge; // true
```