Practical JavaScript Programming - Session 6/8

Practical JavaScript Programming
Session 6
Wilson Su

2
https://www.slideshare.net/sweekson/

3
Wilson Su
Front-end Developer, HIE
● 6 years in web design
● Specialize in JavaScript /
CSS / HTML / OOP / Git
● Familiar with PHP / Design
Pattern
● Interested in UI & Ix Design
wilson_su@trend.com.tw

Outline
4
Chapter 11.
● What’s RegExp?
● Special Characters
● RegExp Flags
● Common Usage
Regular Expression
Chapter 12.
Single Page Application
● What’s SPA?
● Build a Simple SPA
● Demo
Chapter 13.
RESTful Web Services
● What’s RESTful API?
● Build RESTful APIs
● Demo
● Testing Tools

Chapter 11.
Regular Expression
5

What’s Regular Expression?
7
A regular expression is, in theoretical computer science and formal
language theory, a sequence of characters that define a search pattern.
Usually this pattern is then used by string searching algorithms for "find" or
"find and replace" operations on strings. – Wiki
Regular Expression
/^(([^<>()[].,;:s@"]+(.[^<>()[
].,;:s@"]+)*)|(".+"))@(([[0-9]{1,3
}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}]
)|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2,}))$/

Example Scenarios
● Test for a pattern within a string
You can test an input string to see if a telephone number pattern or a credit
card number pattern occurs within the string.
● Replace text
You can use a regular expression to identify specific text in a document and
either remove it completely or replace it with other text.
● Extract a substring from a string based upon a pattern match
You can find specific text within a document or input value
8
What’s RegExp?

Working with Regular Expressions
9
What’s RegExp?
Method Description
regex.exec
Executes a search for a match in a string. It returns an array of
information or null on a mismatch.
regex.test Tests for a match in a string. It returns true or false.
string.match
Executes a search for a match in a string. It returns an array of
information or null on a mismatch.
string.search
Tests for a match in a string. It returns the index of the match, or -1 if
the search fails.
string.replace
Executes a search for a match in a string, and replaces the matched
substring with a replacement substring.
string.split
Uses a regular expression or a fixed string to break a string into an array
of substrings.

Creating a RegExp Object With Ordinary Characters
1. /* Using a regular expression literal */
2. var pattern1 = /earn/;
3.
4. /* Calling the RegExp constructor function */
5. var pattern2 = new RegExp('ear');
6.
7. pattern1.test('learn'); // true
8. pattern1.exec('learn'); // ['earn', index: 1, input: 'learn']
9. 'learn'.search(pattern2); // 1
10. 'learn'.match(pattern2); // ['ear', index: 1, input: 'learn']
11. 'learn'.split(pattern2); // (2) ['l', 'n']
12. 'learn'.replace(pattern2, 'io'); // 'lion'
10

Alternation
12
1. /cat|dog/.test('cat'); // true
2. /cat|dog/.test('dog'); // true
3. /cat|dog/.test('two cats'); // true
4. /cat|dog/.test('xyz'); // false
5. /0|1|2|3|4|5|6|7|8|9/.test('3'); // true
6. /0|1|2|3|4|5|6|7|8|9/.test('12345'); // true
7. /0|1|2|3|4|5|6|7|8|9/.test('I’m 18.'); // true

Lists of Matching Characters
13
1. /[0123456789]/.test('5'); // true
2. /[0-9]/.test('5'); // true
3. /[0-9]/.test('Give me 5'); // true
4. /b[aeiou]t/.test('bot'); // true
5.
6. /[^13579]/.test('5'); // false
7. /[^13579]/.test('2'); // true
8. /[^13579]/.test('52'); // true
9. /[^13579]/.exec('52')[0]; // '2'

Metacharacters
14
Special Characters
Metacharacter Meaning
d Matches a digit character. Equivalent to [0-9].
D Matches a non-digit character. Equivalent to [^0-9].
w
Matches any of the following characters: A-Z, a-z, 0-9, and underscore.
Equivalent to [A-Za-z0-9_].
W
Matches any character except A-Z, a-z, 0-9, and underscore.
Equivalent to [^A-Za-z0-9_].
s
Matches a single white space character, including space, tab, form feed,
line feed.
S Matches a single character other than white space.
. Matches any single character except the newline character n.

Quantifiers
15
Special Characters
Character Meaning
{n} Matches exactly n times. n must be a positive integer.
{n,} Matches at least n times. n must be a positive integer.
{n,m}
Matches at least n and at most m times.
n and m must be positive integers, where n <= m.
*
Matches the preceding character or subexpression zero or more times.
Equivalent to {0,}.
+
Matches the preceding character or subexpression one or more times.
Equivalent to {1,}.
?
Matches the preceding character or subexpression zero or one time.
Equivalent to {0,1}.

Quantifiers
16
1. /[0-9]{5}/.test('123'); // false
2. /[0-9]{5}/.test('12345'); // true
3. /[0-9]{5}/.test('123456789'); // true
4. /[0-9]{5}/.exec('123456789')[0]; // '12345'
5.
6. /[0-9]{5,}/.test('123456789'); // true
7. /[0-9]{5,}/.exec('123456789')[0]; // '123456789'
8.
9. /[0-9]{3,5}/.test('12345'); // true
10. /[0-9]{3,5}/.test('123456789'); // true
11. /[0-9]{3,5}/.exec('123')[0]; // '123'
12. /[0-9]{3,5}/.exec('123456789')[0]; // '12345'

Quantifiers
17
1. /1000*/.test('10'); // false
2. /1000*/.test('100'); // true
3. /1000*/.test('100000'); // true
4. /1000*/.exec('100000')[0]; // '100000'
5.
6. /oh+!/.test('oh!'); // true
7. /oh+!/.test('ohhhh!'); // true
8. /oh+!/.exec('ohhhh!')[0]; // 'ohhhh!'
9.
10. /colou?r/.test('color'); // true
11. /colou?r/.test('colour'); // true

Anchors
18
1. /[a-z][a-z0-9]{3}/.test('0101moris'); // true
2. /^[a-z][a-z0-9]{3}/.test('0101moris'); // false
3. /^[a-z][a-z0-9]{3}/.test('liz'); // false
4.
5. /[A-Z]+!/.test('OMG! XXXX'); // true
6. /[A-Z]+!$/.test('OMG! XXXX'); // false
7. /[A-Z]+!$/.test('OMG!'); // true
8.
9. /^[A-Z][0-9]?$/.test('A'); // true
10. /^[A-Z][0-9]?$/.test('A2'); // true
11. /^[A-Z][0-9]?$/.test('A22'); // false

Anchors
19
1. /is/.test('Chris was a RD.'); // true
2. /bis/.test('Chris was a RD.'); // false
3. /bis/.test('a big issue'); // true
4. /bisb/.test('Chris is a VS.'); // true
5.
6. /Boo/.test('moon'); // true
7. /Boo/.exec('moon')[0]; // 'oo'
8. /Boo/.test('oops'); // false
9. /ooB/.test('oops'); // true
10. /o+B/.exec('ooooops')[0]; // 'ooooo'

Marking the Next Character as a Special Character
20
1. /d+/.test('3+'); // true
2. /^d+$/.test('3+'); // false
3. /^d+$/.test('3+'); // true
4. /^[d+]$/.test('[2]'); // false
5. /^[d+]$/.test('[2]'); // true
6. /[^^]/.test('^'); // false
7. //.test(''); // true

Using Parenthesized Substring Matches
21
1. var string = 'wowwwwww';
2. var pattern = /wow(w*)/;
3. pattern.test(string); // true
4. pattern.exec(string)[0]; // 'wowwwwww'
5. pattern.exec(string)[1]; // 'wwwww'

Global Search
23
1. var string = 'book hook moon';
2. var pattern1 = /w*oow*/;
3. var pattern2 = /w*oow*/g;
4.
5. string.match(pattern1);
6. // ['book', index: 0, input: 'book hook moon']
7.
9. // (3) ['book', 'hook', 'moon']

Case-insensitive Search
24
1. var string = 'A123456789';
2. var pattern1 = /[a-z]w{9}/;
3. var pattern2 = /[a-z]w{9}/i;
4.
5. pattern1.test(string); // false
6. pattern2.test(string); // true

Multi-line Search
25
1. var string = '#, Namern1, Sccotrn2, Rita';
2. var pattern1 = /^d+,s*w+/g;
3. var pattern2 = /^d+,s*w+/m;
4. var pattern3 = /^d+,s*w+/gm;
5.
6. string.match(pattern1); // null
8. // ['1, Sccot', index: 9, input: '#, Name↵1, Sccot↵2, Rita]
10. // (2) ['1, Sccot', '2, Rita']

Do not use RegExp.$n
on production.
26

Using $n with string.replace
27
1. var pattern = /(w+)s(w+)/;
2. var string = 'Pokemon GO';
3.
4. /* This feature is non-standard */
5. string.replace(pattern, '$2, $1!');
6. // 'GO, Pokemon!'
7.
8. string.replace(pattern, (match, $1, $2) => `${$2}, ${$1}!`);
9. // 'GO, Pokemon!'

A JavaScript
RegExp object is stateful.
28

A Javascript Regexp Object Is Stateful
29
1. var string = 'abc';
2. var pattern = /w/g;
3. pattern.exec(string); // ['a', index: 0, input: 'abc']
4. pattern.lastIndex; // 1
5. pattern.exec(string); // ['b', index: 1, input: 'abc']
7. pattern.exec('xyz'); // ['z', index: 2, input: 'xyz']
9. pattern.exec(string); // null

Specifies the Index at Which to Start the Next Match
30
1. var string = '#1 Doran#2 Alexn#3 Ray';
2. var pattern = /#d+sw+/g;
3. pattern.lastIndex = string.lastIndexOf('n');
4. pattern.exec(string);
5. // ['#3 Ray', index: 16, input: '#1 Dora↵#2 Alex↵#3 Ray']

regexp.exec VS. string.match
31
1. var string = '#1 Doran#2 Alex';
2. var pattern1 = /#d+ (w+)/;
3. var pattern2 = /#d+ (w+)/g;
4.
5. pattern1.exec(string); // (2) ['#1 Dora', 'Dora']
6. string.match(pattern1); // (2) ['#1 Dora', 'Dora']
7.
8. pattern2.exec(string); // (2) ['#1 Dora', 'Dora']
9. string.match(pattern2); // (2) ['#1 Dora', '#2 Alex']

Verifying User Inputs
33
1. var input = document.querySelector('input#id');
2. var message = document.querySelector('div#message');
3. var pattern = /^[a-z]d{9}$/i;
4. input.addEventListener('change', function (e) {
5. if (!pattern.test(e.value)) {
6. input.classList.add('invalid');
7. message.textContent = 'Invalid format';
8. }
9. });

Changing Date Format
34
1. var date = '07/26/2017';
2. var pattern = /(dd)/(dd)/(dddd)/;
3. date.replace(pattern, (match, month, date, year) => {
4. return `${year}-${month}-${date}`;
5. });
6. // '2017-07-26'

Extracting Substrings
35
1. var styles = '.btn { color: #222; background: #fff; }';
2. var pattern = /([^s:]+)s*:s*([^;]+)/;
3. styles.match(new RegExp(pattern, 'g')).map((decl) => {
4. var [match, prop, value] = pattern.exec(decl);
5. return { prop, value };
6. });
7. // (2) [{ prop: 'color', value: '#222'}, { prop: 'background',
value: '#fff'}]

Splitting a String Into an Array
36
1. var string = 'web html, css; js';
2. var pattern = /[,;s]+/;
3. keywords.split(string); // (4) ['web', 'html', 'css', 'js']

Some people, when confronted
with a problem, think "I know,
I’ll use regular expressions."
Now they have two problems.
- Jamie Zawinski
37

Chapter 12.
Single-page Application
38

What’s SPA?
40
Single-page Application
A single-page application, or SPA for short, is a web application that fits on
a single web page with the goal of providing a user experience similar to
that of a desktop application. In an SPA, either all necessary code – HTML,
JavaScript, and CSS – is retrieved with a single page load, or the
appropriate resources are dynamically loaded and added to the page as
necessary, usually in response to user actions. – Wiki

Why SPA?
41
What’s SPA?
✓ Speeds up the loading of
secondary pages
✓ Reduced number of resource
requests
✓ Better mobile device experience
✓ Oriented on the apps with a big
amount of interactive client-side
code
✓ Easier state tracking
✗ Speed of initial load can be slow
✗ Complexity of navigation
✗ Not as SEO-friendly as desired
✗ An SPA model breaks the
browser's design for page history
navigation
✗ An SPA will have to call a
function to update the analytics
package
Pros Cons

Technical Approaches
42
What’s SPA?
AJAX WebSocket Server-sent Event
JavaScript
MeteorAngularJS Vue.js
JavaScript Frameworks
…React

The onhashchange Event
43
1. var view = document.querySelector('#view');
2. function render (page) {
3. ajax('get', `/views/${page}.html`).then(html => {
4. view.innerHTML = html;
5. });
6. }
7. window.addEventListener('hashchange', function (e) {
8. render(location.hash.slice(2));
9. });
10. location.hash = '/home';
11. console.log(location.hash); // '#/home'

Using UI Router for URL Routing
44
1. const router = require('3rd-party-ui-router');
2. router
3. .when('/home', () => { /* Displays home page. */ })
4. .when('/posts', () => { /* Displays posts. */ })
5. .when('/posts/:id', () => { /* Displays a post detail. */ })
6. .otherwise('/home');

AngularJS
46
Data Binding
Eases Testing
MVVM
Dependency Injection
Routing
Validations
https://angularjs.org/

SPA URL Design
47
Build a Simple SPA
Todos Create Detail Edit
Title
Notes
Create
porro tepa
Title
laboriosam
mollitia et enim
quasi adipisci quia
Notes
Save
porro tepa
laboriosam mollitia et
enim quasi adipisci quia
provident illum
/todos/:id/edit/todos/:id/todos/create/todos

Project Structure
48
Build a Simple SPA
Project
components
todos
index.js
index.html
create.html
detail.html
edit.html
app.js
styles.css
index.html
Displays todo list
Displays a form for creating a new todo
Displays a todo detail
Displays a form for editing a todo
Todo list module
Entry point
Main page

/index.html
49
1. <!DOCTYPE html>
2. <html ng-app="app">
3. <head>
4. <link rel="stylesheet" href="styles.css">
5. <title>Build a Simple SPA</title>
6. </head>
7. <body>
8. <div ng-view class="view"></div>
9. <script src="https://cdnjs.com/angular.js"></script>
10. <script src="https://cdnjs.com/angular-route.js"></script>
11. <script src="components/todos/index.js"></script>
12. <script src="app.js"></script>
13. </body>
14. </html>

/components/todos/index.js - module.config
50
1. var todos = angular.module('todos', ['ngRoute']);
2. todos.config(function ($routeProvider) {
3. $routeProvider.when('/todos', {
4. templateUrl: 'components/todos/index.html',
5. controller: 'TodosCtrl',
6. resolve: {
7. todolist: (todos) => todos.init()
8. }
9. })
10. .otherwise('/todos');
11. });

/components/todos/index.js - module.service
51
1. todos.service('todos', function ($q, $timeout) {
2. this.data = [];
3. this.loaded = false;
4. this.query = function () {
5. let defer = $q.defer();
6. $timeout(() => {
7. this.data = [{ id: 1, title: 'delectus', … }, … ];
8. defer.resolve(this.data);
9. }, 1000);
10. return defer.promise;
11. };
12. });

/components/todos/index.js - module.controller
52
1. todos.controller('TodosCreateCtrl', function ($scope,
$location, todos) {
2. $scope.todos = todos;
3. $scope.starred = false;
4. $scope.create = function () {
5. todos.create({
6. title: $scope.title,
7. notes: $scope.notes,
8. starred: $scope.starred
9. })
10. .then(() => $location.path('#!/'));
11. };
12. });

/components/todos/index.html
53
1. <h2 class="title">
2. Todos <a class="btn" href="#!/todos/create">✛</a>
3. </h2>
4. <ul class="tasks">
5. <li ng-repeat="todo in todos.data"
6. ng-class="{done:todo.done}">
7. <input type="checkbox" ng-checked="todo.done"
8. ng-model="todo.done">
9. <span class="star"
10. ng-class="{starred:todo.starred}">★</span>
11. <a ng-bind="todo.title" ng-href="#!/todos/{{todo.id}}"></a>
12. </li>
13. </ul>

/app.js
54
1. angular.module('app', [
2. 'todos'
3. ]);

Demo
https://spa-wilson-su.c9users.io/
55

Chapter 13.
56

What’s RESTful API?
58
Representational state transfer or RESTful web services is a way of
providing interoperability between computer systems on the Internet.
REST-compliant Web services allow requesting systems to access and
manipulate textual representations of Web resources using a uniform and
predefined set of stateless operations. – Wiki

Architectural Constraints
59
Client-Server Statelessness Cacheable
Uniform interface Layered system Code-on-demand
(optional)

Relationship Between URL and HTTP Methods
60
Collection, such as
https://api.data.com/items/
Element, such as
https://api.data.com/items/1
GET
List the URIs and perhaps other details of
the collection's members.
Retrieve a representation of the addressed
member of the collection, expressed in an
appropriate Internet media type.
POST
Create a new entry in the collection. The
new entry's URI is assigned automatically
and is usually returned by the operation
Not generally used. Treat the addressed
member as a collection in its own right and
create a new entry within it.
PUT
Replace the entire collection with another
collection.
Replace the addressed member of the
collection, or if it does not exist, create it.
DELETE Delete the entire collection.
Delete the addressed member of the
collection.

Testing Online REST API Using jQuery
1. var host = 'https://jsonplaceholder.typicode.com';
2. var data = { userId: 2, title: 'Aloha' };
3.
4. $.get(`${host}/todos/1`).then((response) => {
5. console.log(response);
6. // {userId: 1, id: 1, title: "delecus au", completed: false}
7. });
8.
9. $.post(`${host}/todos`, data).then((response) => {
10. console.log(response);
11. // {userId: 2, title: "Aloha", id: 201}
12. });
61

63
Node.js
https://nodejs.org/

Installing Node.js on Debian and Ubuntu
64
$ curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -
$ sudo apt-get install -y nodejs

RESTful API
65
Build RESTful APIs
GET https://api-wilson-su.c9users.io/api/todos/
POST https://api-wilson-su.c9users.io/api/todos/
GET https://api-wilson-su.c9users.io/api/todos/:id
PUT https://api-wilson-su.c9users.io/api/todos/:id

Creating a Project Folder
66
$ mkdir spa
$ cd spa
$ touch server.js
$ npm init

Creating a Server
67
1. var http = require('http');
2. http.createServer(function (request, response) {
3. response.writeHead(200, { 'Content-Type': 'text/plain' });
4. response.write('Hello Node.js!');
5. response.end();
6. })
7. .listen(8080, function () {
8. console.log('Listening on port 8080');
9. });

Running the Server
68
$ node server.js
Listening on 8080

Handling Requests
69
1. var http = require('http');
2. var url = require('url');
3. http.createServer(function (request, response) {
4. var pathname = url.parse(request.url, true).pathname;
5. if (//todos/.test(pathname)) { … }
6. else if (//todos/d+/.test(pathname)) { … }
7. else { … }
8. })
9. .listen(8080);

70
Express
http://expressjs.com/

Using Express Web Framework
71
1. /* Install Express in `api` directory:
2. `npm install express --save` */
3. var express = require('express');
4. var app = express();
5. var port = 8080;
6. app.get('/', function (request, response) {});
7. app.get('/todos', function (request, response) {});
8. app.post('/todos', function (request, response) {});
9. app.listen(port, function (err) {
10. console.log('Listening on port ' + port);
11. });

Using Express Router - /routes/todos.js
72
2. var router = express.Router();
3. router.get('/todos', function (req, res) {});
4. router.post('/todos', function (req, res) {});
5. router.get('/todos/:id', function (req, res) {});
6. router.put('/todos/:id', function (req, res) {});
7. module.exports = router;

Mounting the Specified Middleware
73
2. var bodyParser = require('body-parser');
3. var app = express();
4. var port = 8080;
5. app.use(function (req, res, next) {
6. res.setHeader('Access-Control-Allow-Origin', '*');
7. next();
8. });
9. app.use(bodyParser.json());
10. app.use('/', require('./routes/todos'));
11. app.listen(port, function (err) {
12. console.log('Listening on port ' + port);
13. });

Handling Response - GET /todos/:id
74
1. var file = path.resolve(__dirname, '../data/todos.json');
2. router.get('/todos/:id', function(req, res) {
3. fs.readFile(file, (err, text) => {
4. if (err) { throw err; }
5. var todos = JSON.parse(text);
6. var id = Number(req.params.id);
7. var todo = todos.find(v => v.id === id);
8. if (!todo) { return res.status(404).json(null); }
9. res.status(200).json(todo);
10. });
11. });

/data/todos.json
75
1. [{
2. "id": 1,
3. "title": "delectus aut autem",
4. "notes": "",
5. "done": false,
6. "starred": false
7. }, {
8. "id": 2,
9. "title": "quis ut nam facilis et officia qui",
10. "notes": "quo adipisci enim quam ut ab",
11. "done": true,
12. "starred": true
13. }]

Testing APIs Using cURL
78
$ curl "http://localhost/api/todos"
$ curl "http://localhost/api/todos/1"
$ curl -d "title=Water" "http://localhost/api/todos"

80
Postman
https://www.getpostman.com/

81
Postman
https://www.getpostman.com/

Sample Codes
82
SPA
API
https://github.com/sweekson/tm-etp-spa
https://github.com/sweekson/tm-etp-api

Reference
83
● Regular expression - Wikipedia
● Regular Expressions - JavaScript | MDN
● Representational state transfer - Wikipedia
● Single-page application - Wikipedia
● Uses for Regular Expressions | MSDN

Practical JavaScript Programming - Session 6/8

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