reading-notes

Programming with JavaScript

Notes

The control flow is the order in which the computer executes statements in a script. Control flow means that when you read a script, you must not only read from start to finish but also look at program structure and how it affects order of execution. [^1]

A JavaScript function is a block of code designed to perform a particular task. A JavaScript function is executed when “something” invokes it (calls it). [^2]

Declaring a function means making a command/rule

A JavaScript function is defined with the function keyword, followed by a name, followed by parentheses (). Function names can contain letters, digits, underscores, and dollar signs (same rules as variables). The parentheses may include parameter names separated by commas: (parameter1, parameter2, …) The code to be executed, by the function, is placed inside curly brackets: {} [^2]

function name(parameter1, parameter2, parameter3) { // code to be executed }

Function parameters are listed inside the parentheses () in the function definition. Function arguments are the values received by the function when it is invoked. Inside the function, the arguments (the parameters) behave as local variables. [^2]

Function Invocation

The code inside the function will execute when “something” invokes (calls) the function:

• When an event occurs (when a user clicks a button)
• When it is invoked (called) from JavaScript code
• Automatically (self invoked) [^2]

Function Declaration vs Function Expression

• A function declaration
• Function Expression can only call it after it has been defined in the code.

Resources

1. “Control Flow” developer.mozilla.org
2. “JavaScript Functions” w3schools.com
3. “JavaScript Operators” w3schools.com
4. “Expressions and operators” developer.mozilla.org
5. “Functions” developer.mozilla.org

Answers

1. What is control flow?
   • The order in which the computer executes statements in a script
2. What is a JavaScript function?
   • A block of code designed to perform a particular task and executed when something invokes it.
3. What does it mean to invoke - or call - a function?
   • to actually use the function
4. What are the parenthesis () for when you define a function?
   • parameters