Languages - Javascript and Node

Apart from recently added Symbol and Big Int, Javascript primitive data types are:

• string, number, undefined, null, boolean

• string, number, boolean, object, array

• string, number, boolean, object

• string, number, null, boolean

Variable assignment can be done with "let", "const" and "var".

You should use "var" instead of "let" or "const" when (mark all the options you consider to be true):

• You want to ensure your code works on an old browser.

• Never. We should never use "var".

• You want to make sure a down-level scope of your code has access to its value.

• You want to make sure you are able to change the variable value after the first assignment.

Refer to code on the image. On the console, it will appear:

• true

• false

Refer to code on the image. On the console, it will appear:

• true

• false

Refer to the code. Mark the correct answer.

• This code will cause an error.

• No error will occur because we are using "optional chaining" operator.

Refer to the code in the image. We are using "spread" operator to create "myCopy". Choose what will be the equivalent object as the result of the assignment of "myCopy".

• 
• 
• 

We need to print to the console all integers from 0 to 10. Write here the code to it. Hint: using a "for loop" is an option.

Refer to image code. Choose the answer that is the most complete.

• This code won't work. for..of operators are used in objects only.

• This code will work. for..of operators are appropriate to arrays.

• This code will work.

• This code will not work.

In Javascript functions, some variables are passed by reference and some variables are passed by value. Refer to the code. On the console, it will appear:

• "fiat"

• "tesla"

• "undefined"

• An error exception.

Arrow functions allow a shorter sintax. Refer to the code. Choose the correct answer.

• addNumbers1, addNumbers2 and addNumbers3 are equivalent.

• addNumbers1 and addNumbers2 are equivalent but addNumbers3 is different.

• addNumbers1 and addNumbers3 are equivalent but addNumbers2 is different.

• all functions produce different results.