Functions

Question 1

What are functions?

Answer 1

A JavaScript procedure.

A set of statements that performs a task or calculates a value.

Question 2

How can you use a function?

Answer 2

You have to define it somewhere in the scope from which you want to call it.

Question 3

A function consists of the function keyword, followed by __________. ________ enclosed in parentheses, and the _______ enclosed in curly brakets.

Answer 3

the function name.
Parameters.
statements.

Question 4

What are Function Expressions?

Answer 4

A function without a name. It is an anonymous function.

Question 5

A function expression can have a name inside the function to what?

Answer 5

refer to itself

Question 6

When are function expressions convenient over function declarations?

Answer 6

When passing a function as an argument to another function.

Question 7

What are the three ways for a function to refer to itself?

Answer 7

1. the function’s name
2. arguments.callee
3. An in-scope variable that refers to the function

Question 8

What are the two kinds of parameters in functions?

Answer 8

1. Default parameters

2. Rest parameters

Question 9

What is the default parameter for functions?

Answer 9

Undefined

Question 10

How can you change the default parameter?

Answer 10

By assigning a value to the argument name.
eg.)

function hello (a, b = 1) {
}

The default value is now 1 and not undefined.

Question 11

What is the rest parameter?

Answer 11

Allows us to represent an indefinite number of arguments as an array.

Question 12

An arrow function expression lexically binds the ____ value.

Answer 12

this

Question 13

Are arrow functions always anonymous?

Answer 13

Yes

Question 14

What are the two factors influenced the introduction of arrow functions?

Answer 14

Short functions and lexical ‘this’

Question 15

What is the syntax for an function expression?

Answer 15

functionName( => code block );

Question 16

JS built-in function: eval() method

Answer 16

Evaluates JS code represented as a string.

Question 17

JS built-in function: uneval() method

Answer 17

Creates a string representation of the source code of an object.

Question 18

JS built-in function: isFinite() method

Answer 18

Determines whether the passed values is a finite number. If needed, the parameter is first converted to a number.

Question 19

JS built-in function: isNaN() method

Answer 19

Determines whether a value is NaN or not.

Question 20

JS built-in function: parseFloat() method

Answer 20

Parses a string argument and returns an integer of the specified radix (the base in mathematical numeral systems)

Question 21

JS built-in function: parseInt() method

Answer 21

Parses a string argument and returns an integer of the specified radix.

Question 22

JS built-in function: decodeURI() method

Answer 22

Decodes a Uniform Resource Identifier(URI) previously created by encodeURI or by a similar routine.

Question 23

JS built-in function: decodeURIComponent() method

Answer 23

Decodes a Uniform Resource Identifier (URI) component previously created by encodeURIComponent or by a similar routine.

Question 24

JS built-in function: encodeURI() method

Answer 24

Encodes a Uniform Resource Identifier(URI) by replacing each instance of certain characters by one, two, three, or four escape sequences representing the UTF- 8 encoding of the character (will only be four escape sequences for characters composed of two “surrogate” characters).

Question 25

JS built-in function: encodeURICompoment() method

Answer 25

Encodes a Uniform Resource Identifier (URI) component by replacing each instance of certain characters by one, two, three, or four escape sequences representing the UTF-8 encoding of the character (will only be four escape sequences for characters composed of two “surrogate” characters).