feat: throw an error if configuration is invalid

Author: gajus

package.json

@@ -5,6 +5,7 @@
     "url": "http://gajus.com"
   },
   "dependencies": {
+    "ajv": "^4.11.4",
     "babel-plugin-syntax-jsx": "^6.18.0",
     "babel-types": "^6.19.0",
     "generic-names": "^1.0.2",

src/index.js

@@ -6,11 +6,17 @@ import {
 } from 'path';
 import babelPluginJsxSyntax from 'babel-plugin-syntax-jsx';
 import BabelTypes from 'babel-types';
+import Ajv from 'ajv';
+import optionsSchema from './schemas/optionsSchema.json';
 import createObjectExpression from './createObjectExpression';
 import requireCssModule from './requireCssModule';
 import resolveStringLiteral from './resolveStringLiteral';
 import replaceJsxExpressionContainer from './replaceJsxExpressionContainer';
 
+const ajv = new Ajv();
+
+const validate = ajv.compile(optionsSchema);
+
 export default ({
   types: t
 }: {
@@ -170,6 +176,13 @@ export default ({
         }
       },
       Program (path: Object, stats: Object): void {
+        if (!validate(stats.opts)) {
+          // eslint-disable-next-line no-console
+          console.error(validate.errors);
+
+          throw new Error('Invalid configuration');
+        }
+
         const filename = stats.file.opts.filename;
 
         filenameMap[filename] = {

src/schemas/optionsSchema.json

@@ -0,0 +1,23 @@
+{
+  "additionalProperties": false,
+  "properties": {
+    "context": {
+      "type": "string"
+    },
+    "filetypes": {
+      "patternGroups": {
+        ".*": {
+          "type": "string"
+        }
+      },
+      "type": "object"
+    },
+    "generateScopedName": {
+      "type": "string"
+    },
+    "webpackHotModuleReloading": {
+      "type": "boolean"
+    }
+  },
+  "type": "object"
+}