javascript_code_guidelines.md

JavaScript Coding Guidelines

These are guidelines, not rules, but a typical Web application at Ratio should follow most of these.

Casing

• Functions: camelCase
• Properties: up to lead (as long as use is consistent. camelCase is most common.)
• Constants: ALL_CAPS (typically declared with var)
• Class Names (constructors): PascalCase

Syntax

1. Braces

   • Need these on if/else conditionals. Opening brace needs to be on same line not the following line. Important for script minification.

2. Equality & Identity Operators (== vs ===)

   • The equality operator (==) does type coercion while the identity operator (===) does not. Use identity unless absolutely necessary otherwise to avoid "truthy" and "falsey" operations.

   Examples

   • For value types (numbers):
     • a === b returns true if a and b have the same value and are of the same type
   • For reference types:
     • a === b returns true if a and b reference the exact same object
   • For strings:
     • a === b returns true if a and b are both strings and contain the exact same characters

3. Function Variables

   • Variables should be declared at the top of functions to avoid problems caused by variable “hoisting”. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/var

Namespaces

All code should be written to prevent pollution of global namespace.

One approach is the Revealing Module Pattern, but there are many approaches JavaScript Design Patterns

(function(){
	var doStuff = function (){
		// do something
	};
	function doOtherStuff () {
		// do something else
	}

	return {
		doStuff : doStuff
		doOtherStuff : doOtherStuff
	}
})();

Golden Rule of Code

Write the simplest, prettiest, most easy-to-understand code as you can while still getting the job done. Avoid hacks and shortcuts if they lead to poorly-maintainable code.

References