JavaScript Functions 2

Question 1

What is a Higher-Order function?

Answer 1

1. Functions that accept other functions as an Argument.
2. Return a functions output.
3. Or both.

Question 2

How do functions behave like other data types?

Answer 2

Functions can be assigned to variables and then reassigned to a new variable.

const announceThatIAmDoingImportantWork = () => {
console.log(“I’m doing very important work!”);
};

const busy = announceThatIAmDoingImportantWork;

Question 3

What do you not do when assigning an existing function to a new variable OR when passing a callback function as an argument.

Answer 3

Do not invoke the function by adding parenthesis ().

Incorrect - const busy = DoingImportantWork();
This assigns the functions return value to the variable.

Correct - const busy = DoingImportantWork;
This assigns the existing function to the new variable.

Question 4

What is a first-class object?

Answer 4

They have properties and methods. For example a function is a first-class object.

Question 5

How do you find the original name of a function?

Answer 5

Use the name property.

const isTwoPlusTwo = checkThatTwoPlusTwo;

isTwoPlusTwo();

console.log(isTwoPlusTwo.name);

Question 6

What is a callback function?

Answer 6

A function that gets passed as an argument to a higher-order function.

The callback function is invoked when the higher-order function is called.

Question 7

What is an anonymous function?

Answer 7

A function without a name, an anonymous function can be an argument to.