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Javascript-Coding Style

 

Coding conventions secure quality:

 

  • Improves code readability
  • Make code maintenance easier

 

Syntax:

 

Javascript-Coding Style

 

Variable Names:

 

You use camelCase for identifier names variables and functions.

All names start with a letter.

 

Syntax:

 

firstName = "I2tutorials";
lastName = "javascript";

price = 19.90;
tax = 0.20;

fullPrice = price + (price * tax);

 

Spaces Around Operators:

 

Always put spaces around operators ( = + – * / ), and after commas:

 

Syntax:

 

var x = y + z;
var values = ["java", "css", "html"];

 

Code Indentation:

 

Always use two spaces for indentation of code blocks:

 

Syntax:

 

function toCelsius(fahrenheit) {
 return (5 / 9) * (fahrenheit - 32);
}

 

Statement Rules:

 

Always end a simple statement with a semicolon.

 

Syntax:

 

var values = ["html", "css", "javascript"];

var person = {
 firstName: "I2",
 lastName: "Tutorials",
 age: 50,
 eyeColor: "green"
};

 

General rules for complex or compound statements:

 

  • Place the opening brackets at the end of the first line.
  • Use one space before the opening brackets.
  • Place the closing brackets on a new line, without leading spaces.
  • Do not end a complex or compound statement with a semicolon.

 

Functions:

 

function toCelsius(fahrenheit) {
 return (5 / 9) * (fahrenheit - 32);
}

 

Loops:

 

for (i = 0; i < 5; i++) {
 x += i;
}

 

Conditionals:

 

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

 

Object Rules:

 

  • Place the opening brackets on the same line as the object name.
  • Use colon plus (: +)one space between each property and its value.
  • Use quotes (” “,’ ‘)around string values, not around numeric values.
  • Do not add a comma(,) after the last property-value pair.
  • Place the closing brackets on a new line, without leading spaces.
  • Always end an object definition with a semicolon(;).

 

Example

 

var person = {
 firstName: "I2",
 lastName: "Tutorials",
 age: 50,
 eyeColor: "green"
};

 

Naming Conventions:

 

  • Variable and function names are written as camelCase.
  • Global variables are written in UPPERCASE (We don’t, but it’s quite common).
  • Constants (like PI) written in UPPERCASE.