add CACHE_DIR envvar

README.md

@@ -90,4 +90,5 @@ You can self-host the API yourself, if you so wish! Here's the rough steps:
 You can pass these into the server as config (an `.env` file will **not** work):
 
 - `API_KEY`: A Google API key - see [this guide](https://theoephraim.github.io/node-google-spreadsheet/#/guides/authentication?id=api-key) to see how to get one hassle-free
-- `PORT`: The HTTP port to host the server on
+- `PORT`: The HTTP port to host the server on
+- `CACHE_DIR`: The directory to store cached data in, defaults to `./cache/`

index.js

@@ -6,7 +6,7 @@ import path from 'path';
 import { request } from 'undici';
 import PQueue from 'p-queue';
 
-const cacheFolder = './cache/';
+const cacheFolder = process.env.CACHE_DIR || './cache/';
 
 let levels = {
   nlw: {