Advanced Concepts Problems

Question 1

All:
https://javascriptweblog.wordpress.com/2010/07/06/function-declarations-vs-function-expressions/

Answer 1

https://javascriptweblog.wordpress.com/2010/07/06/function-declarations-vs-function-expressions/

Question 2

Hoisting and the var Statement:
https://launchschool.com/lessons/43f23069/assignments/39f50f91

Answer 2

https://launchschool.com/lessons/43f23069/assignments/39f50f91

Question 3

Strict Mode
Problem at bottom of page
https://launchschool.com/gists/406ba491

Answer 3

https://launchschool.com/gists/406ba491

Question 4

Closures:
https://launchschool.com/lessons/43f23069/assignments/9362d2cf

Answer 4

https://launchschool.com/lessons/43f23069/assignments/9362d2cf

Question 5

Private data,
at bottom of page:
https://launchschool.com/lessons/43f23069/assignments/3df10c91

Answer 5

https://launchschool.com/lessons/43f23069/assignments/3df10c91

Question 6

IIFE
https://launchschool.com/lessons/43f23069/assignments/69bab49c

Answer 6

https://launchschool.com/lessons/43f23069/assignments/69bab49c

Question 7

Shorthand:
https://launchschool.com/lessons/43f23069/assignments/c6c682cd

Answer 7

https://launchschool.com/lessons/43f23069/assignments/c6c682cd

Question 8

do this but with no conditional statements

Answer 8

https://launchschool.com/exercises/81b953d7?track=javascript

Question 9

do this (doesn’t work so good with hidden data)
https://launchschool.com/exercises/d30df1f2?track=javascript

Answer 9

https://launchschool.com/exercises/d30df1f2?track=javascript

Question 10

Advanced concepts quiz:
https://launchschool.com/quizzes/a669620d

Answer 10

https://launchschool.com/quizzes/a669620d

Question 11

What does this do?
var foo = 10;

function bar() {
if (foo > 20) {
var foo = 50;
}

console.log(foo);
foo += 10;
}

bar();
bar();
bar();

Answer 11

The declaration for foo on line 5 of the original code gets hoisted to a function-scoped variable, foo, that shadows the foo variable on line 2. Since we’re not initializing the variable inside bar, its value is undefined, and that’s what gets logged each time we execute line 8 in the original code.

function bar() {
var foo;
if (foo > 20) {
foo = 50;
}

console.log(foo);
foo += 10;
}

var foo;
foo = 10;

bar();
bar();
bar();

Question 12

The following code has console.log calls on lines 1, 4, 8, 10, and 16. In what sequence will those 5 log calls execute? (or not at all?)

console.log(foo());

function foo() {
console.log(‘Waiting for bar!’);
}

function foo() {
console.log(foo);
function bar() {
console.log(‘bar again’);
}

bar();

function bar() {
console.log(‘bar again and again’);
}
}

Answer 12

8 16 1