Expression, Operator, and Function

An expression evaluates into a single value:

1. The expression that assigns a value to a variable
2. The expression that uses 2 or more values to return a single value

The operator creates a single value from one or more values. Types of operators:

• Arithmetic operators:
  • +: addition
  • -: subtraction
  • *: multiplication
  • **: exponentiation
  • /: division
  • %: modulus
  • ++: increment
  • --: decrement
• Assignment Operators:
  • =
  • +=
  • -=
  • *=
  • /=
  • %=
  • **=
• String operators:
  • +:
    • Adding two numbers will return the sum
    • Adding a number and a string will return a string
• Comparison operators:
  • ==: equal to
  • ===: equal value and equal type
  • !=: not equal
  • !==: not equal value or not equal type
  • >: greater than
  • <: less than
  • >=: greater than or equal to
  • <=: less than or equal to
  • ?: ternary operator
• Logical operators:
  • &&: logical and

  • : logical or

  • !: logical not
• Type operators:
  • typeof: returns the type of a variable
  • instanceof: returns true if an object is an instance of an object type

Functions let you group a series of statements together to perform a specific task. Tips of using a function:

• Declare a function using the function keyword
• Give the function a name followed by parentheses
• The statements that perform the task sit in a code block
• Functions can be used as variable values
• Variables declared within a function become LOCAL to the function

<==Back