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Clean code.pptx

Parveen Soni
Parveen Soni

The document discusses common code smells and refactoring practices. It provides examples of code smells such as poor naming conventions, long parameter lists, duplicate code, nested conditions, and variable declarations. It then provides recommendations on how to refactor code to address these smells. This includes using meaningful names, splitting methods, avoiding unnecessary comments, following DRY principles, reducing nesting, and declaring variables closer to use. OOPs concepts like abstraction, encapsulation, polymorphism are also mentioned. The overall document aims to educate developers on identifying and fixing bad code smells to improve code quality.

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Clean Code Practices Parveen Soni https://github.com/parveen-rx
Agenda Common Code smells and Code refactoring
Common Code Smells Poor Names (mysterious name) Poor Naming conventions (meaningless name) Poor Method Signatures Long Parameter List Code comments Duplicate code Nested Conditions Variable Declaration on the Top? Magic Numbers OOPS Concepts
Poor Names (Mysterious Names) Code Smell Mysterious Names SqlDataReader dr1; Int od; void Button1_click(); class Page1 {} Need to investigate documentation or usage and then understand the meaning of the declaration Code fix SqlDataReader sqlDataReader; Int order; void check_availability(); class ViewCustomerPage {} Meaningful from the name itself
Poor Names (Meaningless Names) void beginCheckFunctionality_StoreCl ientSideCheckBoxIDsArray() Need to understand usage and implementation to get idea of what method is doing Usually, such function have 100 LOC to make it more complex. Code fix Method such be 20 LOC/30LOC Divide into sub-methods and given short and meaningful name to each functionality
Poor Method Signature def user = userService.getUser(username, password, false) Fn getUser(String uName, String pass, bool login ) { if(login){ //get from DB return user } else { //get from redis return user } } Code fix Divide if else into sub-method to avoid doing that Fn getUserFromDB(String uName, String pass) { //get from DB return user } Fn getUserFromRedis(String uName, String pass) { //get from Redis return user }
Long Parameter List checkCurrentNotification (userName, password, userType DateTime.now()) checkNotificationForUser (userName, password, userType) checkTodayNotificationForUser (userName, password, userType, 1 day diff) Code fix Create a subclass with below property class User { String userName String password UserTypeEnum userType }
Code Comments Dont write comments, rewrite the code! Dont explain whats (the obvious) Explain whys and hows
Avoid Duplicate Code String fetchLastLoginInGMT(){ // some date logic //convert in GMT return datetime; } String fetchLastLogin(){ //some date logic //convert to usertimezone return datetime; } String fetchLastLogin( TZ tz = GMT) { //some date logic //covert to tz if defined return datetime; } * Follow DRY (Dont repeat yourself)
Nested Conditions 1. If() {} else{} 2. If() { if(){} } 3. if(a){ if(b) { //set some params} } If(c) { if(b) { //set some params} } 1. Use ternary operator 2. Combine statements using AND OR operations 3. Swap orders if(b){ if(a) { //set some params} if(c) { //set some params} }
Nested Conditions (contd.) Writing multiple if else Overusing ternary operator Use switch statement Dont overuse use it with sense
Variables declaration on the top Declaration of variables at top method (){ int count =0; int sub_count=0; if() { if(){ if() { count =1; sub_count=2; } } } } Declare variables as close to the first spot that you use them as possible. Declare variables at top when need to use globally and multiple times. It's not really anything to do with efficiency but makes your code much more readable. The closer a variable is declared to where it is used, the less scrolling/searching you must do when reading the code later.
OOPS Concepts Abstraction Design Patterns Encapsulation Polymorphism Inheritance Association Aggregation Composition
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Clean code.pptx

  • 2. Agenda Common Code smells and Code refactoring
  • 3. Common Code Smells Poor Names (mysterious name) Poor Naming conventions (meaningless name) Poor Method Signatures Long Parameter List Code comments Duplicate code Nested Conditions Variable Declaration on the Top? Magic Numbers OOPS Concepts
  • 4. Poor Names (Mysterious Names) Code Smell Mysterious Names SqlDataReader dr1; Int od; void Button1_click(); class Page1 {} Need to investigate documentation or usage and then understand the meaning of the declaration Code fix SqlDataReader sqlDataReader; Int order; void check_availability(); class ViewCustomerPage {} Meaningful from the name itself
  • 5. Poor Names (Meaningless Names) void beginCheckFunctionality_StoreCl ientSideCheckBoxIDsArray() Need to understand usage and implementation to get idea of what method is doing Usually, such function have 100 LOC to make it more complex. Code fix Method such be 20 LOC/30LOC Divide into sub-methods and given short and meaningful name to each functionality
  • 6. Poor Method Signature def user = userService.getUser(username, password, false) Fn getUser(String uName, String pass, bool login ) { if(login){ //get from DB return user } else { //get from redis return user } } Code fix Divide if else into sub-method to avoid doing that Fn getUserFromDB(String uName, String pass) { //get from DB return user } Fn getUserFromRedis(String uName, String pass) { //get from Redis return user }
  • 7. Long Parameter List checkCurrentNotification (userName, password, userType DateTime.now()) checkNotificationForUser (userName, password, userType) checkTodayNotificationForUser (userName, password, userType, 1 day diff) Code fix Create a subclass with below property class User { String userName String password UserTypeEnum userType }
  • 8. Code Comments Dont write comments, rewrite the code! Dont explain whats (the obvious) Explain whys and hows
  • 9. Avoid Duplicate Code String fetchLastLoginInGMT(){ // some date logic //convert in GMT return datetime; } String fetchLastLogin(){ //some date logic //convert to usertimezone return datetime; } String fetchLastLogin( TZ tz = GMT) { //some date logic //covert to tz if defined return datetime; } * Follow DRY (Dont repeat yourself)
  • 10. Nested Conditions 1. If() {} else{} 2. If() { if(){} } 3. if(a){ if(b) { //set some params} } If(c) { if(b) { //set some params} } 1. Use ternary operator 2. Combine statements using AND OR operations 3. Swap orders if(b){ if(a) { //set some params} if(c) { //set some params} }
  • 11. Nested Conditions (contd.) Writing multiple if else Overusing ternary operator Use switch statement Dont overuse use it with sense
  • 12. Variables declaration on the top Declaration of variables at top method (){ int count =0; int sub_count=0; if() { if(){ if() { count =1; sub_count=2; } } } } Declare variables as close to the first spot that you use them as possible. Declare variables at top when need to use globally and multiple times. It's not really anything to do with efficiency but makes your code much more readable. The closer a variable is declared to where it is used, the less scrolling/searching you must do when reading the code later.
  • 13. OOPS Concepts Abstraction Design Patterns Encapsulation Polymorphism Inheritance Association Aggregation Composition