JS Coding Conventions

Coding conventions are style guidelines for programming.

They typically cover:

• Naming and declaration rules for variables and functions.
• Rules for the use of white space, indentation, and comments.
• Programming practices and principles

Coding conventions secure quality:

• Improves code readability
• Make code maintenance easier

General JavaScript code conventions used by W3Schools:

1. Variable And Function Names
   • camelCase
   • start with a letter
   • Global variables & Constants written in UPPERCASE
   • Hyphens are not allowed in JavaScript names.
2. Spaces Around Operators
3. Code Indentation
   • Always use 4 spaces
   • Do not use tabs (tabulators) for indentation. Different editors interpret tabs differently.
4. Always end a simple statement with a semicolon
5. General rules for complex (compound) statements:
   • Put the opening bracket at the end of the first line.
   • Use one space before the opening bracket.
   • Put the closing bracket on a new line, without leading spaces.
   • Do not end a complex statement with a semicolon.
   • EX:

     if (time < 20) {
      greeting = "Good day";
     }
     

6. Line Length
   • if tool long, break it after an operator or a comma.

Use Lower Case File Names

• Most web servers (Apache, Unix) are case sensitive about file names:
  • EX: london.jpg cannot be accessed as London.jpg.
• Other web servers (Microsoft, IIS) are not case sensitive:
  • EX: london.jpg can be accessed as London.jpg or london.jpg.
• Always use lower case file names (if possible).

Performance

• Coding conventions are not used by computers. Most rules have little impact on the execution of programs.
• Indentation and extra spaces are not significant in small scripts.
• For code in development, readability should be preferred. Larger production scripts should be minified.