102-07: Programming With JavaScript

Operators

• Unary: Single operand (before or after)
• Binary: Two operands, one before and one after operator
• Ternary: Conditionals

Assignment Operators

• Assign first (left) operand a value determined by the second (right) operand
• = is the simplest assignment operator, assigning the second operand value to the first operand
• Compound assignment operators abbreviate operations (Listed Here)
• Can be used to evaluate a variable and assign a new value, like:
• a = f(); , which would assign the value/result of f() to variable a ; or:
• let b = z(); which results in an initial assignment for b of the value of z()
• Can be chained/nested–to be used with caution– to be used in function calls assingment of other variables, and more (right-associative, evaluated left-to-right)

Comparison Operators

• Return a logic value depending on the comparison (“true”)
• Converts some values to equivalent type if possible
• === and !== (equality and inequality operators) do not convert
• (Listed Here)

Arithmetic Operators

• Return a single numerical value
• Standard arithmetics (+-*/) as well as others listed Here
• Can be used with strings (like for concatenation of text with +)

Logical Operators

• && - logical “and”
• || - logical “or”
• ! - logical “not”

Functions

• Take input and return related output
• Must be defined from where it is called
• Anatomy: Name, parenthetical parameters (with commas between), JavaScript definition (in curled brackets)
• Names can contain letters, digits, _, and $
• The values received by the function when invoked are called arguments, which are locally variables within the function
• Declared with the function keyword, setting the following text as the declared function’s name, like:function TriAdd(firsts, seconds, thirds) { return firsts+seconds+thirds; }
• User-defined objects that are parameters can be changed outside the scope of that function
• The definition of a function does not execute it
• Calling the function executes it

Control Flow

• Control Flow: Order of execution of script statements
• Executes from top line to bottom except for conditional or looping structures