JS Functions

Question 1

What is a function in JavaScript?

Answer 1

A function is a special kind of object that is “callable”.

It is a group of actions that are repeatable.

Question 2

Describe the parts of a function definition.

Answer 2

A function definition has the keyword function, followed by a name (optional), parentheses ( ), and curly braces { }. Within the ( ) are parameters (optional). Within { } is the code block, which might include a return statement (optional).

Question 3

Describe the parts of a function call.

Answer 3

A function call has the name of the function, followed by parentheses ( ). Within the parentheses are arguments.

Question 4

What two effects does a return statement have on the behavior of a function?

Answer 4

1) Causes the function to produce a value we can use in our program; saves the value
2) Prevents any more code in the function’s code block from being run.

Question 5

Why are function parameters useful?

Answer 5

Parameters give variability to the function.

They serve as placeholders for variables whose value is unknown until the function is called to pass an argument.

Question 6

What is the difference between a parameter and an argument?

Answer 6

Parameters are declared when defining a function; have no value and receives a value when a function is called.
Arguments are passed when calling a function

Question 7

When comparing them side-by-side, what are the differences between a function call and a function definition?

Answer 7

Function definition: has the keyword ‘function’, has curly brackets { } with a code block nested within the brackets.
Function call: simply has the name of the function, followed by parentheses ( ).

Question 8

In JavaScript, when is a function’s scope determined; when it is called or when it is defined?

Answer 8

Defined

Question 9

What allows JavaScript functions to “remember” values from their surroundings?

Answer 9

Closures

Question 10

What must the return value ofmyFunctionbe if the following expression is possible? myFunction()();

Answer 10

Must return a function

Question 11

What does this code do? const wrap = value => () => value;

Answer 11

Const wrap = function (value) {
	function () {
		return value
	}
}