# Variables

# Concepts

• In WXS, all variables reference values.
• Undeclared variables that use directly assigned values are defined as global variables.
• If you declare a variable but do not assign a value, its default value is undefined.
• The var performance is consistent with JavaScript and variable hoisting is performed.

var foo = 1;
var bar = "hello world";
var i; // i === undefined

The above code declares three variables: foo, bar, and i. Then, foo is assigned the value of 1 and bar is assigned the string value "hello world".

# Variable Names

Variable names must comply with the following rules:

• The first character must be an English letter (a-z, A-Z) or underscore (_).
• The remaining characters can be English letters (a-z, A-Z), underscores (_), or numbers (0-9).

# Reserved Identifiers

The following identifiers cannot be used as variable names:

delete
void
typeof

null
undefined
NaN
Infinity
var

if
else

true
false

require

this
function
arguments
return

for
while
do
break
continue
switch
case
default