Interactive fun quiz about new generation of JavaScript for your front end developers that will make them sweat and swear

1. ES6 King
Interactive fun quiz about new generation of
JavaScript for your front end developers that will
make them sweat and swear

2. ES6 King
Interactive fun quiz about new generation of
JavaScript for your front end developers that will
make them sweat and swear

3. ES6 King
ES2015
Interactive fun quiz about new generation of
JavaScript for your front end developers that will
make them sweat and swear

4. Rules
4 teams
4 possible answers
1 minute per question
1 winner
The answer must be explained
12 questions

5. Rules
4 teams
4 possible answers
1 minute per question
1 winner
The answer must be explained
12 questions

6. Rules
4 teams
4 possible answers
1 minute per question
1 winner
The answer must be explained
12 questions

7. Rules
4 teams
4 possible answers
1 minute per question
1 winner
The answer must be explained
12 questions

8. Rules
4 teams
4 possible answers
1 minute per question
1 winner
The answer must be explained
12 questions

9. Rules
4 teams
4 possible answers
1 minute per question
1 winner
The answer must be explained
12 questions

10. Ready?
Steady!
Go!

11. 01
Question01

12. let x = 42;
if (true) {
console.log(x);
let x = 1337;
}
What’s the result of
the console.log
operation?
1. 42
2. undefined
3. Error
4. 1337

13. let x = 42;
if (true) {
console.log(x);
let x = 1337;
}
What’s the result of
the console.log
operation?
1. 42
2. undefined
3. Error
4. 1337

14. 01
Question02

15. var x = `foo ${y}`,
y = `bar ${x}`;
console.log(y);
What’s the result of
this code?
1. bar foo bar
undefined
2. bar foo
undefined
3. bar foo
4. InternalError

16. What’s the result of
this code?
var x = `foo ${y}`,
y = `bar ${x}`;
console.log(y);
1. bar foo bar
undefined
2. bar foo
undefined
3. bar foo
4. InternalError

17. 01
Question03

18. What’s the result of
this code?
1. 1
2. 3
3. [1,2,3]
4. Error
((...x, xs)=>x)(1,2,3)

19. What’s the result of
this code?
((...x, xs)=>x)(1,2,3)
1. 1
2. 3
3. [1,2,3]
4. Error

20. 01
Question04

21. (new function f () {
this.a = 1;
return ((...b) => {
return this.a;
}).bind({ a: 9 });
})();
What’s the result of
this code?
1. 9
2. undefined
3. TypeError
4. 1

22. (new function f () {
this.a = 1;
return ((...b) => {
return this.a;
}).bind({ a: 9 });
})();
What’s the result of
this code?
1. 9
2. undefined
3. TypeError
4. 1

23. 01
Question05

24. let x, { x: y = 1 } = { x }; y;
What’s the result of
this code?
1. undefined
2. 1
3. {x: 1}
4. Error

25. What’s the result of
this code?
let x, { x: y = 1 } = { x }; y;
1. undefined
2. 1
3. {x: 1}
4. Error

26. 01
Question06

27. typeof (function* f() {
yield f;
})().next()
What’s the result of
this code?
1. “function”
2. “generator”
3. “object”
4. Error

28. typeof (function* f() {
yield f;
})().next()
What’s the result of
this code?
1. “function”
2. “generator”
3. “object”
4. Error

29. 01
Question07

30. class MyClass {
const MY_CONST = 'string';
constructor() {
this.MY_CONST;
}
}
let myClass = new MyClass();
console.log(myClass.MY_CONST);
What’s the result of
this code?
1. ‘string’
2. SyntaxError
3. undefined
4. ReferenceError

31. class MyClass {
const MY_CONST = 'string';
constructor() {
this.MY_CONST;
}
}
let myClass = new MyClass();
console.log(myClass.MY_CONST);
What’s the result of
this code?
1. ‘string’
2. SyntaxError
3. undefined
4. ReferenceError

32. 01
Question08

33. function* g() {
return 1;
}
for (let i of g())
console.log(i);
What’s the result of
this code?
1. 1
2. Error
3. undefined
4. [object Object]

34. function* g() {
return 1;
}
for (let i of g())
console.log(i);
What’s the result of
this code?
1. 1
2. Error
3. undefined
4. [object Object]

35. 01
Question09

36. let popo = (function*() {
console.log([yield, yield]);
}());
popo.next(1);
popo.next(2);
popo.next(3);
What’s the result of
this code?
1. [1,2]
2. [2,3]
3. [1,undefined]
4. Error

37. let popo = (function*() {
console.log([yield, yield]);
}());
popo.next(1);
popo.next(2);
popo.next(3);
What’s the result of
this code?
1. [1,2]
2. [2,3]
3. [1,undefined]
4. Error

38. 01
Question10

39. What’s the result of
this code?
1. f, f, f
2. f, t, f
3. f, t, t
4. t, t, t
class X {}
class Y extends X {}
console.log(Object.getPrototypeOf(X) ===
Function.prototype);
console.log(Object.getPrototypeOf(Y) === X);
console.log(Object.getPrototypeOf(new Y()) ===
Y.prototype)

40. What’s the result of
this code?
1. f, f, f
2. f, t, f
3. f, t, t
4. t, t, t
class X {}
class Y extends X {}
console.log(Object.getPrototypeOf(X) ===
Function.prototype);
console.log(Object.getPrototypeOf(Y) === X);
console.log(Object.getPrototypeOf(new Y()) ===
Y.prototype)

41. 01
Question11

42. What’s the result of
this code?
1. []
2. [2,3,4,5,1]
3. [5,4,3,2,1]
4. Error
let f = (x, ...y) => x?[...f(...y), x]:[];
let arr = [], i = 0;
for (arr[i++] of f(1,2,3,4,5)) {}
console.log(arr);

43. What’s the result of
this code?
1. []
2. [2,3,4,5,1]
3. [5,4,3,2,1]
4. Error
let f = (x, ...y) => x?[...f(...y), x]:[];
let arr = [], i = 0;
for (arr[i++] of f(1,2,3,4,5)) {}
console.log(arr);

44. 01
Question12

45. What’s the result of
this code?
1. [1,2]
2. 3
3. 4
4. 5 let m = new Map([[1,2],[[1,2],3],[2,4],[3,5]]);
console.log(m.get([...m][1][1]));

46. What’s the result of
this code?
1. [1,2]
2. 3
3. 4
4. 5 let m = new Map([[1,2],[[1,2],3],[2,4],[3,5]]);
console.log(m.get([...m][1][1]));

47. And the
winner is...

48. Thank You
credits:
● Afonso Matos
● Juriy Zaytsev
● Dmitry Soshnikov
● Kim Gysen
● Ben Katz
● Sergey Bolshchikov