Podcast
Questions and Answers
Given the principle of avoiding code duplication, which scenario exemplifies the most effective use of a function?
Given the principle of avoiding code duplication, which scenario exemplifies the most effective use of a function?
- Implementing a function to encapsulate a block of code that performs a unique, one-time calculation.
- Using a function to define a variable that is used only once in the program.
- Creating a function that duplicates existing built-in functionalities, such as re-implementing the `alert()` function.
- Employing a function to execute the same series of steps repeatedly across different parts of an application. (correct)
What distinguishes a function declaration from other types of JavaScript code blocks?
What distinguishes a function declaration from other types of JavaScript code blocks?
- Function declarations are automatically executed upon being defined, unlike other code blocks.
- A function declaration defines a named block of code that can be invoked multiple times throughout a program. (correct)
- Function declarations are only used for mathematical operations.
- Function declarations can only be defined within other functions.
Consider a function calculateArea(width, height) designed to compute the area of a rectangle. Which of the following reflects the correct syntax for invoking this function?
Consider a function calculateArea(width, height) designed to compute the area of a rectangle. Which of the following reflects the correct syntax for invoking this function?
- `calculateArea[width, height];`
- `calculateArea(5, 10);` (correct)
- `function.calculateArea(width, height);`
- `calculateArea = width * height;`
What is the scope of a variable declared inside a function?
What is the scope of a variable declared inside a function?
If a variable with the same name exists both inside and outside a function, how does the function treat these variables?
If a variable with the same name exists both inside and outside a function, how does the function treat these variables?
Given the concept of functions as 'building blocks', which of the following strategies best employs functions to enhance code maintainability and readability?
Given the concept of functions as 'building blocks', which of the following strategies best employs functions to enhance code maintainability and readability?
In what way do functions minimize redundancy and enhance code reusability?
In what way do functions minimize redundancy and enhance code reusability?
What is the primary difference between calling a built-in function, such as alert(), and a user-defined function?
What is the primary difference between calling a built-in function, such as alert(), and a user-defined function?
How does the use of parameters in a function enhance its versatility and applicability?
How does the use of parameters in a function enhance its versatility and applicability?
If a function is defined to accept two arguments but is called with only one, what typically happens in JavaScript?
If a function is defined to accept two arguments but is called with only one, what typically happens in JavaScript?
Flashcards
Functions
Functions
Reusable blocks of code that perform a specific task.
Function Declaration
Function Declaration
A way to create a function using the function keyword.
Function Keyword
Function Keyword
The keyword used to define a function.
Function Name
Function Name
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Parameters
Parameters
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Function Body
Function Body
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Calling a Function
Calling a Function
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Code Reusability
Code Reusability
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Local Variable
Local Variable
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Variable Scope (within a function)
Variable Scope (within a function)
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Study Notes
- Functions are the main building blocks of a program
- Functions allow code to be called many times without duplication
- Built-in functions include
alert(message),prompt(message, default)andconfirm(question) - Custom functions can also be created
Function Declaration
- Functions are created using a function declaration
- Start with the
functionkeyword - Followed by the function name
- Then a list of parameters in parentheses, separated by commas (can be empty)
- Finally, the function body in curly braces
Function Syntax
function name(parameter1, parameter2,... parameterN) { // body }
Calling a Function
- Functions are called by their name followed by parentheses:
showMessage() - Calling the function executes the code within its body
Avoiding Code Duplication
- Functions help avoid code duplication
- Changes only need to be made in one place: the function definition
Local Variables
- Variables declared inside a function are only visible within that function
- Local variables are not accessible outside the function
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Description
Functions are fundamental building blocks in programming, enabling code reuse and preventing duplication. Built-in functions like alert, prompt, and confirm exist, and custom functions can be created using function declarations. Declaring a function involves the function keyword, a name, parameters, and a body.
