代码质量与重构

  • 当你写了一大堆代码,你没有意识到里面有一大堆重复。
  • 当你写了一大堆测试,却不知道覆盖率有多少。

这就是个问题了，于是偶然间看到了一个叫code climate的网站。

Code Climate

Code Climate consolidates the results from a suite of static analysis tools into a single, real-time report, giving your team the information it needs to identify hotspots, evaluate new approaches, and improve code quality.

Code Climate整合一组静态分析工具的结果到一个单一的，实时的报告，让您的团队需要识别热点，探讨新的方法，提高代码质量的信息。

简单地来说:

  • 对我们的代码评分
  • 找出代码中的坏味道

于是，我们先来了个例子

Rating Name Complexity Duplication Churn C/M Coverage
A lib/coap/coap_request_handler.js 24 0 6 2.6 46.4%
A lib/coap/coap_result_helper.js 14 0 2 3.4 80.0%
A lib/coap/coap_server.js 16 0 5 5.2 44.0%
A lib/database/db_factory.js 8 0 3 3.8 92.3%
A lib/database/iot_db.js 7 0 6 1.0 58.8%
A lib/database/mongodb_helper.js 63 0 11 4.5 35.0%
C lib/database/sqlite_helper.js 32 86 10 4.5 35.0%
B lib/rest/rest_helper.js 19 62 3 4.7 37.5%
A lib/rest/rest_server.js 17 0 2 8.6 88.9%
A lib/url_handler.js 9 0 5 2.2 94.1%

分享得到的最后的结果是:

[Coverage][1]

代码的坏味道

于是我们就打开lib/database/sqlite_helper.js，因为其中有两个坏味道

Similar code found in two :expression_statement nodes (mass = 86)

在代码的 lib/database/sqlite_helper.js:58…61 < >

  1.     SQLiteHelper.prototype.deleteData = function (url, callback) {
  2.         'use strict';
  3.         var sql_command = "DELETE FROM  " + config.table_name + "  where " + URLHandler.getKeyFromURL(url) + "=" + URLHandler.getValueFromURL(url);
  4.         SQLiteHelper.prototype.basic(sql_command, callback);

lib/database/sqlite_helper.js:64…67 < >

与

  1. SQLiteHelper.prototype.getData = function (url, callback) {
  2.     'use strict';
  3.     var sql_command = "SELECT * FROM  " + config.table_name + "  where " + URLHandler.getKeyFromURL(url) + "=" + URLHandler.getValueFromURL(url);
  4.     SQLiteHelper.prototype.basic(sql_command, callback);

只是这是之前修改过的重复。。

原来的代码是这样的

  1. SQLiteHelper.prototype.postData = function (block, callback) {
  2.     'use strict';
  3.     var db = new sqlite3.Database(config.db_name);
  4.     var str = this.parseData(config.keys);
  5.     var string = this.parseData(block);
  7.     var sql_command = "insert or replace into " + config.table_name + " (" + str + ") VALUES (" + string + ");";
  8.     db.all(sql_command, function (err) {
  9.         SQLiteHelper.prototype.errorHandler(err);
  10.         db.close();
  11.         callback();
  12.     });
  13. };
  15. SQLiteHelper.prototype.deleteData = function (url, callback) {
  16.     'use strict';
  17.     var db = new sqlite3.Database(config.db_name);
  18.     var sql_command = "DELETE FROM  " + config.table_name + "  where " + URLHandler.getKeyFromURL(url) + "=" + URLHandler.getValueFromURL(url);
  19.     db.all(sql_command, function (err) {
  20.         SQLiteHelper.prototype.errorHandler(err);
  21.         db.close();
  22.         callback();
  23.     });
  24. };
  26. SQLiteHelper.prototype.getData = function (url, callback) {
  27.     'use strict';
  28.     var db = new sqlite3.Database(config.db_name);
  29.     var sql_command = "SELECT * FROM  " + config.table_name + "  where " + URLHandler.getKeyFromURL(url) + "=" + URLHandler.getValueFromURL(url);
  30.     db.all(sql_command, function (err, rows) {
  31.         SQLiteHelper.prototype.errorHandler(err);
  32.         db.close();
  33.         callback(JSON.stringify(rows));
  34.     });
  35. };

说的也是大量的重复，重构完的代码

  1. SQLiteHelper.prototype.basic = function(sql, db_callback){
  2.     'use strict';
  3.     var db = new sqlite3.Database(config.db_name);
  4.     db.all(sql, function (err, rows) {
  5.         SQLiteHelper.prototype.errorHandler(err);
  6.         db.close();
  7.         db_callback(JSON.stringify(rows));
  8.     });
  10. };
  12. SQLiteHelper.prototype.postData = function (block, callback) {
  13.     'use strict';
  14.     var str = this.parseData(config.keys);
  15.     var string = this.parseData(block);
  17.     var sql_command = "insert or replace into " + config.table_name + " (" + str + ") VALUES (" + string + ");";
  18.     SQLiteHelper.prototype.basic(sql_command, callback);
  19. };
  21. SQLiteHelper.prototype.deleteData = function (url, callback) {
  22.     'use strict';
  23.     var sql_command = "DELETE FROM  " + config.table_name + "  where " + URLHandler.getKeyFromURL(url) + "=" + URLHandler.getValueFromURL(url);
  24.     SQLiteHelper.prototype.basic(sql_command, callback);
  25. };
  27. SQLiteHelper.prototype.getData = function (url, callback) {
  28.     'use strict';
  29.     var sql_command = "SELECT * FROM  " + config.table_name + "  where " + URLHandler.getKeyFromURL(url) + "=" + URLHandler.getValueFromURL(url);
  30.     SQLiteHelper.prototype.basic(sql_command, callback);
  31. };

重构完后的代码比原来还长，这似乎是个问题~~