feat: use custom config path with --config arg (#10)

* feat: use custom config path with `--config` arg
* Added README

Author: serrg

README.md

@@ -73,3 +73,13 @@ scripts: {
     "make-types": "make-federated-types --outputDir ../../my_types/"
 }
 ```
+
+#### `package.json`
+
+If you would like to specify custom path to the config, you can pass `--config` parameter like so:
+
+```json
+scripts: {
+    "make-types": "make-federated-types --config ./path/to/my/config.json --outputDir ../../my_types/"
+}
+```

cli.js

@@ -15,6 +15,11 @@ const outputDir = outDirArg
     ? path.resolve('./', outDirArg)
     : path.resolve(__dirname, '../../@types/__federated_types/');
 
+const configPathArg = getArg('--config');
+const configPath = configPathArg
+    ? path.resolve(configPathArg)
+    : null;
+
 const findFederationConfig = (base) => {
     let files = fs.readdirSync(base);
     let queue = [];
@@ -34,7 +39,13 @@ const findFederationConfig = (base) => {
     }
 };
 
-const federationConfigPath = findFederationConfig('./');
+if (configPath && !fs.existsSync(configPath)) {
+    console.error(`ERROR: Unable to find a provided config: ${configPath}`);
+    process.exit(1);
+}
+
+const federationConfigPath = configPath || findFederationConfig('./');
+
 
 if (federationConfigPath === undefined) {
     console.error(`ERROR: Unable to find a federation.config.json file in this package`);