fix(config loader): deal with config file charset (#525)

make sure that config file charset is utf-8, or throw detail to notify.
for #465 [Question] SyntaxError: Parsing JSON at for commitizen config failed

Author: hxzhao527

Diff for: package.json

@@ -85,6 +85,7 @@
     "lodash": "4.17.11",
     "minimist": "1.2.0",
     "shelljs": "0.7.6",
+    "strip-bom": "3.0.0",
     "strip-json-comments": "2.0.1"
   },
   "babel": {

Diff for: src/configLoader/getContent.js

@@ -2,6 +2,8 @@ import fs from 'fs';
 import path from 'path';
 
 import stripJSONComments from 'strip-json-comments';
+import isUTF8 from 'is-utf8';
+import stripBom from 'strip-bom';
 
 import { getNormalizedConfig } from '../configLoader';
 
@@ -17,7 +19,7 @@ export default getConfigContent;
 function readConfigContent (configPath) {
     const parsedPath = path.parse(configPath)
     const isRcFile = parsedPath.ext !== '.js' && parsedPath.ext !== '.json';
-    const jsonString = fs.readFileSync(configPath, 'utf-8');
+    const jsonString = readConfigFileContent(configPath);
     const parse = isRcFile ?
       (contents) => JSON.parse(stripJSONComments(contents)) :
       (contents) => JSON.parse(contents);
@@ -61,3 +63,20 @@ function getConfigContent (configPath, baseDirectory) {
     const content = readConfigContent(resolvedPath);
     return getNormalizedConfig(configBasename, content);
 };
+
+/**
+ * Read proper content from config file.
+ * If the chartset of the config file is not utf-8, one error will be thrown.
+ * @param {String} configPath
+ * @return {String}
+ */
+function readConfigFileContent (configPath) {
+
+  let rawBufContent = fs.readFileSync(configPath);
+
+  if (!isUTF8(rawBufContent)) {
+    throw new Error(`The config file at "${configPath}" contains invalid charset, expect utf8`);
+  }
+
+  return stripBom(rawBufContent.toString("utf8"));
+}

Diff for: test/fixtures/invalid-charset.json

@@ -13,6 +13,8 @@ describe('configLoader', function () {
       .to.throw(/parsing json at/i);
     expect(() => getContent('invalid-json-rc', fixturesPath))
       .to.throw(/parsing json at/i);
+    expect(() => getContent('invalid-charset.json', fixturesPath))
+      .to.throw(/contains invalid charset/i);
   });
 
   it('parses json files with comments', function () {