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

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

How to try ES6 and Beyond with on Windows

(1) Open Command Line with “Run as Administrator”

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

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

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

(4) notepad link.cmd

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

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

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

(8) notepad 1.js

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

(10) babel-node 1.js

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

More on .

Math

Set

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

function sumArray(arr){

}

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)

function wordHistogram(str){

}

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]

function unionsAndSort(a,b){

}

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’

function onlyStartWithA(str){

}

Exercises(5) Reverse Digits of an Integer

reverseDigit(123); //=> 321 reverseDigit(-456); //=> 654

function reverseDigit(num){

}