refactor(config): add parse function (#39)

update README

packages/config/README.md

@@ -0,0 +1,84 @@
+# @dzangolab/fastify-config
+
+A [Fastify](https://github.com/fastify/fastify) plugin that defines an opinionated config for an API.
+
+When registered on a Fastify instance, the plugin will:
+
+* decorate the Fastify instance with the `config` object, available with the `config` attribute.
+* decorate all requests with the `config` object, available with the `config` attribute; this can be used to construct a `buildContext` for mercurius resolvers, for example.
+* decorate the Fastfy instance with a `hostname` attribute.
+
+## Installation
+
+In a simple repo:
+
+```bash
+npm install @dzangolab/fastify-config --save-dev
+```
+
+If using in a monorepo with pnpm:
+
+```bash
+pnpm add -D --filter "myrepo" @dzangolab/fastify-config
+```
+
+## Usage
+
+Somewhere in your code, create a `config.ts` file that looks like this:
+
+```javascript
+import { parse } from "@dzangolab/fastify-config";
+import dotenv from "dotenv";
+
+import type { ApiConfig } from "@dzangolab/fastify-config";
+
+dotenv.config();
+
+const config: ApiConfig = {
+  appName: process.env.APP_NAME as string,
+  appOrigin: (process.env.APP_ORIGIN as string).split(","),
+  baseUrl: process.env.BASE_URL as string,
+  env: parse(process.env.NODE_ENV, "development") as string,
+  logger: {
+    level: parse(process.env.LOG_LEVEL, "error") as string,
+  },
+  name: process.env.NAME as string,
+  pagination: {
+    default_limit: parse(process.env.PAGINATION_DEFAULT_LIMIT, 25) as number,
+    max_limit: parse(process.env.PAGINATION_MAX_LIMIT, 50) as number,
+  },
+  port: parse(process.env.PORT, 20040) as number,
+  protocol: parse(process.env.PROTOCOL, "http") as string,
+  rest: {
+    enabled: parse(process.env.REST_ENABLED, true) as boolean,
+  },
+  version: `${process.env.npm_package_version || process.env.API_VERSION}+${process.env.API_BUILD || "local"}` as string,
+};
+
+export default config;
+```
+
+Register the plugin with your Fastify instance:
+
+```javascript
+import configPlugin from "@dzangolab/fastify-config";
+import fastify from "fastify";
+
+import config from "./config";
+
+import type { ApiConfig } from "@dzangolab/fastify-config";
+import type { FastifyInstance } from "fastify";
+
+// Create fastify instance
+const fastify = Fastify({
+  logger: config.logger,
+});
+
+// Register fastify-config plugin
+fastify.register(configPlugin, { config });
+
+await fastify.listen({
+  port: config.port,
+  host: "0.0.0.0",
+ });
+```

packages/config/src/index.ts

@@ -3,6 +3,29 @@ import FastifyPlugin from "fastify-plugin";
 import type { ApiConfig } from "./types";
 import type { FastifyInstance, FastifyRequest } from "fastify";
 
+const parse = (
+  value: string | undefined,
+  fallback: boolean | number | string | undefined
+) => {
+  if (value === undefined) {
+    return fallback;
+  }
+
+  switch (typeof fallback) {
+    case "boolean": {
+      return !!JSON.parse(value);
+    }
+
+    case "number": {
+      return JSON.parse(value);
+    }
+
+    default: {
+      return value;
+    }
+  }
+};
+
 const plugin = async (
   fastify: FastifyInstance,
   options: { config: ApiConfig },
@@ -36,4 +59,6 @@ declare module "fastify" {
 
 export default FastifyPlugin(plugin);
 
+export { parse };
+
 export * from "./types";