This document provides instructions for setting up ES6 and beyond on Windows and includes 5 exercises to practice additional ES6 features including: 1) writing a function to sum all elements in an array, 2) writing a function to count word frequencies in a string, 3) writing a function to union and sort two arrays, 4) writing a function to select words starting with 'a' or 'A' from a string, and 5) writing a function to reverse the digits of an integer.

1. Lecture 3: Additional
Materials for ES6
ES6 on Windows + More ES6 + More
Exercises
Kobkrit Viriyayudhakorn, Ph.D.
CEO of iApp Technology Limited.
kobkrit@gmail.com
http://www.kobkrit.com

2. All source code
• https://github.com/kobkrit/learn-react-native

3. How to try ES6 and Beyond
with on Windows
(1) Open Command Line with “Run as Administrator”

4. (2) Create Directory at C:es6 and then run “npm init”

5. (3) Press Enter Many Times Until All Questions are Answered

6. (4) npm install --save-dev babel-cli
babel-preset-stage-0

7. (4) notepad link.cmd

8. (5) Type “doskey babel-node=.node_modules.binbabel-
node $*” and hit file > save

9. (6) Go back to command line, type “link.cmd”

10. (7) echo {"presets":["stage-0"]} > .babelrc

11. (8) notepad 1.js

12. (9) Type down some ES6 code, e.g.,
console.log(‘Hello World!’); + Hit Save

13. (10) babel-node 1.js

14. Alias is not persistence!
• If you closed the command line windows, enter c:
es6 again, and always run link.cmd
• Open command line program
• cd c:es6
• link.cmd
• babel-node somefile.js

15. More on .

16. Math

18. Set

19. Exercise
(1) Write down a function that sum every element in
array. E.g. sumArray([12,3,4,1,2,3]) = 25
sumArray([12,3,4,1,2,3]); //=> 25
sumArray([1,2,3]); //=> 6

20. function sumArray(arr){
}

21. Exercise
(2) Write function that count word size case-insensitively.
wordHistogram('Hello world hello earth')
//=> {hello : 2, world : 1, earth : 1 }
wordHistogram('dog eat cat cat eat dog')
//=> {dog : 2, eat : 2, cat : 2 }
wordHistogram('Na na na na na na na na na
na na na na na na na na na na na na na na
na Batman!’)
//=> {Batman! : 1, na: 24}
(https://www.youtube.com/watch?v=EtoMN_xi-AM)

22. function wordHistogram(str){
}

23. Exercises
(3) Write the function that can unions two arrays and
sort it ascendingly.
unionsAndSort([5,3,2],[1,4,5]) // =>
[1,2,3,4,5,5]
unionsAndSort([1,2,3],[4]) // =>
[1,2,3,4]

24. function unionsAndSort(a,b){
}

25. Exercises
(4) Write the function that select only words that start
with letter ‘a’ or ‘A’ in a string.
onlyStartWithA(‘angulus is an angle in
latin’); //=> ‘angulus an angle’
onlyStartWithA(‘apple is not an
animal’); //=> ‘apple an animal’

26. function onlyStartWithA(str){
}

27. Exercises
(5) Reverse Digits of an Integer
reverseDigit(123); //=> 321
reverseDigit(-456); //=> 654

28. function reverseDigit(num){
}