Chap. 3 eloquent javascript

Question 1

Functions that don’t have a return statement at all, such as makeNoise, similarly return_____________.

Answer 1

undefined

Question 2

let x = 10;
if (true) {
  let y = 20;
  var z = 30;
  console.log(x + y + z);
  // → 60
}

// IS Y VISIBLE?

Answer 2

// y is not visible here

Question 3

let x = 10;
if (true) {
  \_\_\_ y = 20;
  \_\_\_ z = 30;
  console.log(x + y + z);
  // → 60
}

// what keyword to use to make Y NOT visible and Z VISBLE

Answer 3

let Y

var Z

Question 4

const halve = function(n) {
  return n / 2;
};

let n = 10;
console.log(halve(100));
// → 
console.log(n);
// →

Answer 4

// → 50
// → 10

Question 5

FUNCTION DECLARTION OR EXPRESSION

function square(x) {
  return x * x;
}

Answer 5

FUNCTION DECLARTION

Question 6

_____________are not part of the regular top-to-bottom flow of control.

Answer 6

Function declarations

Question 7

FUNCTION DECLARTION OR EXPRESSION

var square = function(x){
  return x * x;
}

Answer 7

FUNCTION EXPRESSION

Question 8

The main difference between a function expression and a function statement is the function name, which can be omitted in function expressions to ________

Answer 8

create anonymous functions.

Question 9

CONDENSE the code:

const square1 = (x) => { return x * x; };

Answer 9

const square1 = x => x * x;

Question 10

//Write out as a arrow function

function funcName(params) {
   return params + 2;
 }

Answer 10

var funcName = (params) => params + 2

Question 11

When an arrow function has no parameters at all, its parameter list is just ______________.

Answer 11

an empty set of parentheses.

Question 12

function greet(who) {
  console.log("Hello " + who);
}
greet("Harry");
console.log("Bye");

Answer 12

“Hello Harry”

“Bye”

Question 13

function square(x) { return x * x; }
console.log(square(4, true, "hedgehog"));
// →

Answer 13

// → 16

Question 14

We defined function with only one parameter. Yet when we call it with three, the language doesn’t complain. It ignores the extra arguments and computes the square of the ______

Answer 14

first argument

Question 15

If you pass too few, the missing parameters in a function get assigned the value ____________

Answer 15

undefined.

Question 16

function minus(a, b) {
  if (b === undefined) return -a;
  else return a - b;
}

console. log(minus(10));
console. log(minus(10, 5));

Answer 16

// → -10
// → 5

Question 17

console.log(undefined === undefined);

Answer 17

TRUE

Question 18

TRUE OR FALSE

If you write an = operator after a parameter, followed by an expression, the value of that expression will replace the argument when it is not given.

Answer 18

TRUE

Question 19

A function that calls itself is called___________.

Answer 19

recursive

Question 20

When you only have one parameter in an arrow function, the opening parenthesis are optional:

TRUE OR FALSE

Answer 20

TRUE

https://codeburst.io/javascript-arrow-functions-for-beginners-926947fc0cdc

Question 21

In a arrow function if you are returning an expression, you remove ____________

Answer 21

the brackets

Question 22

var myCar = new Car('Ford', 'Escape');
console.log(myCar);
// ?

Answer 22

=> Car {make: “Ford”, model: “Escape”}

Question 23

function add(c, d) {
  console.log(this.a + this.b + c + d);
}
add(3,4);
// logs  and why

Answer 23

NaN

a and b are undefined