JavaScript Functions Worksheet
Question 1
What is a function, and why would you ever want to use one in your code?
A function is a reusable block of code designed to perform a specific task. Functions are defined once and can be executed multiple times, often with different inputs (parameters).
Question 2
What do you call the values that get passed into a function?
The values passed into a function are called arguments. These arguments correspond to the parameters defined in the function's declaration.
For example: function add(a, b) {
return a + b; // 'a' and 'b' are parameters
}
let sum = add(3, 4); // 3 and 4 are arguments
console.log(sum); // Outputs: 7
Question 3
What is the 'body' of a function, and what are the characters that enclose the body of a function?
The body of a function is the part of the function where the actual code or logic is written. It contains the statements that execute when the function is called.
The body of a function is enclosed within curly braces {}.
For example:function sayHello() {
console.log("Hello, world!"); // This is the function body
}
Question 4
What does it mean to 'call', or 'invoke' a function (note that 'calling' and 'invoking' a function mean the same thing)?
To call or invoke a function means to execute the code inside the function by using its name followed by parentheses, optionally passing arguments. This tells the program to perform the task defined within the function.
Question 5
If a function has more than one parameter, what character do you use to separate those parameters?
When a function has more than one parameter, the parameters are separated by a comma (,).
Question 6
What is the problem with this code (explain the syntax error)?
function convertKilometersToMiles(km)
return km * 0.6217;
}
The problem with this code lies in the missing curly braces {} for the function body. In JavaScript, when a function's body contains multiple statements, or even a single statement without proper syntax, it must be enclosed in curly braces. Without them, JavaScript doesn't know where the function's body begins and ends, leading to a syntax error.
Here’s the corrected code:
function convertKilometersToMiles(km)
return km * 0.6217; // Function body enclosed within curly braces
}
Question 7
In the code below, there are two functions being invoked.
Which one returns a value? Explain why you know this.
const name = prompt("Enter your name");
alert("Hello " + name + "!");
The prompt() function returns a value (user input), while alert() does not—it only displays a message.
Coding Problems
Coding Problems - See the 'script' tag below this h3 tag. You will have to write some JavaScript code in it.
Always test your work! Check the console log to make sure there are no errors.