Show error on failing to parse .tldrrc (#366)

Author: T3sT3ro

lib/config.js

@@ -16,8 +16,9 @@ exports.get = () => {
   try {
     customConfig = JSON.parse(fs.readFileSync(CUSTOM));
   } catch (ex) {
-    /*eslint-disable */
-    /*eslint-enable */
+    if (ex instanceof SyntaxError) {
+      throw new Error('The content of .tldrrc is not a valid JSON object:\n' + ex);
+    }
   }
 
   let merged = defaults(customConfig, defaultConfig);

test/config.spec.js

@@ -18,7 +18,11 @@ describe('Config', () => {
   "repository": "http://myrepo/assets/tldr.zip"
 }`;
 
-  const CUSTOM_INVALID =
+  const CUSTOM_INVALID_JSON =
+`# comments are not allowed in json
+{}`;
+
+  const CUSTOM_INVALID_SCHEMA =
 `
 {
   "themes": {
@@ -53,9 +57,15 @@ describe('Config', () => {
     config.get().repository.should.eql('http://myrepo/assets/tldr.zip');
   });
 
-  it('should validate the custom config format', () => {
+  it('should validate the custom config JSON', () => {
+    fs.readFileSync.onCall(0).returns(DEFAULT);
+    fs.readFileSync.onCall(1).returns(CUSTOM_INVALID_JSON);
+    config.get.should.throw(/not a valid JSON object/);
+  });
+
+  it('should validate the custom config schema', () => {
     fs.readFileSync.onCall(0).returns(DEFAULT);
-    fs.readFileSync.onCall(1).returns(CUSTOM_INVALID);
+    fs.readFileSync.onCall(1).returns(CUSTOM_INVALID_SCHEMA);
     config.get.should.throw(/Invalid theme value/);
   });