test: add jest unit tests, prettier w/ config and .editorconfig

jest unit tests are implemented in engine.test.js and have achieve 100% code coverage and all tests
are passing. also add prettier and .editorconfig and reformatted files

Author: yinzara

.editorconfig

@@ -0,0 +1,8 @@
+[*]
+end_of_line = lf
+charset = utf-8
+indent_size = 2
+indent_style = space
+insert_final_newline = true
+max_line_length = 80
+trim_trailing_whitespace = true

.prettierrc

@@ -0,0 +1,5 @@
+{
+  "printWidth": 80,
+  "endOfLine": "lf",
+  "singleQuote": true
+}

.travis.yml

@@ -4,6 +4,7 @@ node_js:
   - 10
   - 8
   - 6
+  - 4
 
 jobs:
   include:

engine.js

@@ -1,10 +1,10 @@
-"format cjs";
+'format cjs';
 
 var wrap = require('word-wrap');
 var map = require('lodash.map');
 var longest = require('longest');
 var rightPad = require('right-pad');
-var chalk = require('chalk')
+var chalk = require('chalk');
 
 var filter = function(array) {
   return array.filter(function(x) {
@@ -13,39 +13,41 @@ var filter = function(array) {
 };
 
 var headerLength = function(answers) {
-  return answers.type.length + 2 + (answers.scope ? answers.scope.length + 2 : 0)
-}
+  return (
+    answers.type.length + 2 + (answers.scope ? answers.scope.length + 2 : 0)
+  );
+};
 
 var maxSummaryLength = function(options, answers) {
-  return options.maxHeaderWidth - headerLength(answers)
-}
+  return options.maxHeaderWidth - headerLength(answers);
+};
+
 var filterSubject = function(subject) {
   subject = subject.trim();
   if (subject.charAt(0).toLowerCase() !== subject.charAt(0)) {
-    subject = subject.charAt(0).toLowerCase() + subject.slice(1, subject.length);
+    subject =
+      subject.charAt(0).toLowerCase() + subject.slice(1, subject.length);
   }
   while (subject.endsWith('.')) {
-    subject = subject.slice(0, subject.length - 1)
+    subject = subject.slice(0, subject.length - 1);
   }
-  return subject
-}
+  return subject;
+};
 
 // This can be any kind of SystemJS compatible module.
 // We use Commonjs here, but ES6 or AMD would do just
 // fine.
-module.exports = function (options) {
-
+module.exports = function(options) {
   var types = options.types;
 
   var length = longest(Object.keys(types)).length + 1;
-  var choices = map(types, function (type, key) {
+  var choices = map(types, function(type, key) {
     return {
       name: rightPad(key + ':', length) + ' ' + type.description,
       value: key
     };
   });
 
-
   return {
     // When a user runs `git cz`, prompter will
     // be executed. We pass you cz, which currently
@@ -59,7 +61,13 @@ module.exports = function (options) {
     // By default, we'll de-indent your commit
     // template and will keep empty lines.
     prompter: function(cz, commit) {
-      console.log('\nLine 1 will have the maximum length of ' + options.maxHeaderWidth + ' characters (enforced). All other lines will be wrapped after ' + options.maxLineWidth + ' characters.\n');
+      console.log(
+        '\nLine 1 will have the maximum length of ' +
+          options.maxHeaderWidth +
+          ' characters (enforced). All other lines will be wrapped after ' +
+          options.maxLineWidth +
+          ' characters.\n'
+      );
 
       // Let's ask some questions of the user
       // so that we can populate our commit
@@ -72,61 +80,83 @@ module.exports = function (options) {
         {
           type: 'list',
           name: 'type',
-          message: 'Select the type of change that you\'re committing:',
+          message: "Select the type of change that you're committing:",
           choices: choices,
           default: options.defaultType
-        }, {
+        },
+        {
           type: 'input',
           name: 'scope',
-          message: 'What is the scope of this change (e.g. component or file name): (press enter to skip)',
+          message:
+            'What is the scope of this change (e.g. component or file name): (press enter to skip)',
           default: options.defaultScope,
           filter: function(value) {
             return value.trim().toLowerCase();
           }
-        }, {
+        },
+        {
           type: 'input',
           name: 'subject',
-          message: function (answers) {
-            return 'Write a short, imperative tense description of the change (max ' + maxSummaryLength(options, answers) + ' chars):\n'
+          message: function(answers) {
+            return (
+              'Write a short, imperative tense description of the change (max ' +
+              maxSummaryLength(options, answers) +
+              ' chars):\n'
+            );
           },
           default: options.defaultSubject,
           validate: function(subject, answers) {
-            var filteredSubject = filterSubject(subject)
-            return filteredSubject.length == 0 ? 'Subject is required' :
-                filteredSubject.length <= maxSummaryLength(options, answers) ? true :
-                'Subject length must be less than or equal to ' + maxSummaryLength(options, answers) + ' characters. Current length is ' + filteredSubject.length + ' characters.';
+            var filteredSubject = filterSubject(subject);
+            return filteredSubject.length == 0
+              ? 'subject is required'
+              : filteredSubject.length <= maxSummaryLength(options, answers)
+              ? true
+              : 'Subject length must be less than or equal to ' +
+                maxSummaryLength(options, answers) +
+                ' characters. Current length is ' +
+                filteredSubject.length +
+                ' characters.';
           },
           transformer: function(subject, answers) {
-            var filteredSubject = filterSubject(subject)
-            var color = filteredSubject.length <= maxSummaryLength(options, answers) ? chalk.green : chalk.red
-            return color('(' + filteredSubject.length + ') ' + subject)
+            var filteredSubject = filterSubject(subject);
+            var color =
+              filteredSubject.length <= maxSummaryLength(options, answers)
+                ? chalk.green
+                : chalk.red;
+            return color('(' + filteredSubject.length + ') ' + subject);
           },
           filter: function(subject) {
-            return filterSubject(subject)
+            return filterSubject(subject);
           }
-        }, {
+        },
+        {
           type: 'input',
           name: 'body',
-          message: 'Provide a longer description of the change: (press enter to skip)\n',
+          message:
+            'Provide a longer description of the change: (press enter to skip)\n',
           default: options.defaultBody
-        }, {
+        },
+        {
           type: 'confirm',
           name: 'isBreaking',
           message: 'Are there any breaking changes?',
           default: false
-        }, {
+        },
+        {
           type: 'input',
           name: 'breaking',
           message: 'Describe the breaking changes:\n',
           when: function(answers) {
             return answers.isBreaking;
           }
-        }, {
+        },
+        {
           type: 'confirm',
           name: 'isIssueAffected',
           message: 'Does this change affect any open issues?',
           default: options.defaultIssues ? true : false
-        }, {
+        },
+        {
           type: 'input',
           name: 'issues',
           message: 'Add issue references (e.g. "fix #123", "re #123".):\n',
@@ -136,11 +166,11 @@ module.exports = function (options) {
           default: options.defaultIssues ? options.defaultIssues : undefined
         }
       ]).then(function(answers) {
-
         var wrapOptions = {
           trim: true,
+          cut: true,
           newline: '\n',
-          indent:'',
+          indent: '',
           width: options.maxLineWidth
         };
 
@@ -150,17 +180,19 @@ module.exports = function (options) {
         // Hard limit this line in the validate
         var head = answers.type + scope + ': ' + answers.subject;
 
-        // Wrap these lines at 72 characters
+        // Wrap these lines at options.maxLineWidth characters
         var body = answers.body ? wrap(answers.body, wrapOptions) : false;
 
         // Apply breaking change prefix, removing it if already present
         var breaking = answers.breaking ? answers.breaking.trim() : '';
-        breaking = breaking ? 'BREAKING CHANGE: ' + breaking.replace(/^BREAKING CHANGE: /, '') : '';
+        breaking = breaking
+          ? 'BREAKING CHANGE: ' + breaking.replace(/^BREAKING CHANGE: /, '')
+          : '';
         breaking = breaking ? wrap(breaking, wrapOptions) : false;
 
         var issues = answers.issues ? wrap(answers.issues, wrapOptions) : false;
 
-        commit(filter([ head, body, breaking, issues ]).join('\n\n'));
+        commit(filter([head, body, breaking, issues]).join('\n\n'));
       });
     }
   };