Variables & DataTypes

Question 1

Which datatype is this?

“Hello”

Answer 1

String

Question 2

Which datatype is this?

42

Answer 2

Number, and in the category Number it’s an integer

Question 3

Which datatype is this?

true

Answer 3

Boolean

Question 4

Which datatype is this? And what is inside?

[‘hey’, ‘hello’, ‘hi’]

Answer 4

Array of strings

Question 5

Which datatype is this? And what is inside?

[1, 2, 3]

Answer 5

Array of integers/numbers

Question 6

Which datatype is this?

4.05

Answer 6

Number, and in the category Number it’s a float.

Question 7

Is het: const, let of var?

“the identifier can not be reassigned”

Answer 7

const

Question 8

Is het: const, let of var?

“I am looking at code that was written before ES6 came out”

Answer 8

var

Question 9

Is het: const, let of var?

“the identifier can be overwritten”

Answer 9

let

Question 10

Which datatype is this?

false

Answer 10

Boolean

Question 11

Which datatype is this?

{greeting: “hello”}

Answer 11

Object with 1 property

The key is greeting and the value “hello”.
The value is a String.

Question 12

Which datatype is this?

{
greeting: “hello”,
arrayWithNumbers: [1,2,3]
}

Answer 12

Object with 2 properties.

2 keys: greeting and arrayWithNumbers
the value of greeting is a String.
the value of arrayWithNumber is an Array.

Question 13

Wat is de index van de first item of an Array?

Answer 13

The first index is 0

Question 14

Hoe kun je het aantal items in een Array zien?

Answer 14

de .length property, voorbeeld: myArray.length

dit is een property van de Array en heeft daarom geen haken aan het einde

Question 15

Hoe kun je een item toevoegen aan een Array?

Answer 15

De push method, voorbeeld: myArray.push(item)

dit is een array method, met andere worden in de kern is het een functie, daarom zijn hier ronde haken () aanwezig.