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This repository was archived by the owner on Apr 8, 2025. It is now read-only.

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vilterpvilterp
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now you can instantly like posts on jankyblog with ajax
1 parent abac28c commit 937ed8f

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10 files changed

+207
-81
lines changed

10 files changed

+207
-81
lines changed

‎basic.html‎

Lines changed: 6 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,15 +1,17 @@
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<html>
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<head>
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<title>My First JS</title>
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</head>
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<body>
6-
<button id="mybutton">Click Me</button>
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<script type="text/javascript">
85
function sayHello() {
96
alert('Hello from JavaScript!');
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console.log('hello in the console');
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}
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document.getElementById('mybutton').addEventListener('click', sayHello);
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document.addEventListener('DOMContentLoaded', function() {
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document.getElementById('mybutton').addEventListener('click', sayHello);
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});
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</script>
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</head>
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<body>
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<button id="mybutton">Click Me</button>
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</body>
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</html>

‎dom1.html‎

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@@ -1,23 +1,28 @@
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<html>
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<head>
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<title>My First JS</title>
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<script type="text/javascript">
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document.addEventListener('DOMContentLoaded', function() {
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// click list
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var clicks = 0;
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var click_list = document.getElementById('clicklist');
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function addClick() {
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clicks += 1;
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var li = document.createElement('li');
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li.innerText = 'click #' + clicks.toString();
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click_list.appendChild(li);
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}
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document.getElementById('mybutton').addEventListener('click', addClick);
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});
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</script>
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</head>
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<body>
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<p>
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<button id="mybutton">Click Me</button>
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</p>
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<ul id="clicklist"></ul>
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<script type="text/javascript">
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// click list
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var clicks = 0;
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var click_list = document.getElementById('clicklist');
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function addClick() {
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clicks += 1;
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var li = document.createElement('li');
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li.innerText = 'click #' + clicks.toString();
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click_list.appendChild(li);
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}
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document.getElementById('mybutton').addEventListener('click', addClick);
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</script>
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</body>
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</html>

‎dom2.html‎

Lines changed: 11 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -1,19 +1,21 @@
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<html>
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<head>
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<title>My First JS</title>
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<script type="text/javascript">
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document.addEventListener('DOMContentLoaded', function() {
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// chars in text box
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var text_box = document.getElementById('text_box');
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var chars_display = document.getElementById('chars_display');
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function updateDisplay() {
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chars_display.innerText = text_box.value.length;
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}
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text_box.addEventListener('keyup', updateDisplay);
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});
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</script>
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</head>
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<body>
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<p>
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<input type="text" id="text_box"/> Chars: <span id="chars_display"></span>
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</p>
9-
<script type="text/javascript">
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// chars in text box
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var text_box = document.getElementById('text_box');
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var chars_display = document.getElementById('chars_display');
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function updateDisplay() {
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chars_display.innerText = text_box.value.length;
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}
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text_box.addEventListener('keyup', updateDisplay);
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</script>
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</body>
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</html>

‎janky-blog/jankydb.js‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,62 @@
1+
var fs = require('fs');
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function JankyDB(path) {
4+
this.path = path;
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if(!this.exists()) {
6+
this.initialize();
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console.log('initialized db');
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}
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}
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JankyDB.prototype.exists = function() {
12+
return fs.existsSync(this.path);
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}
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JankyDB.prototype.initialize = function() {
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var initial = {
17+
next_post_id: 0,
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posts: []
19+
};
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fs.writeFileSync(this.path, JSON.stringify(initial, undefined, 2));
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}
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JankyDB.prototype.getPosts = function(callback) {
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fs.readFile(this.path, function(err, res) {
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if(err) throw err;
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callback(JSON.parse(res).posts);
27+
});
28+
}
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30+
JankyDB.prototype.addPost = function(post, callback) {
31+
var _this = this;
32+
fs.readFile(this.path, function(err, res) {
33+
if(err) throw err;
34+
var db = JSON.parse(res);
35+
post.id = db.next_post_id++;
36+
db.posts.push(post);
37+
fs.writeFile(_this.path, JSON.stringify(db, undefined, 2), function(err, res) {
38+
if(err) throw err;
39+
if(callback) callback(post.id);
40+
});
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});
42+
}
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44+
JankyDB.prototype.changePostLikes = function(post_id, delta, callback) {
45+
var _this = this;
46+
fs.readFile(this.path, function(err, res) {
47+
if(err) throw err;
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var db = JSON.parse(res);
49+
for(var i=0; i < db.posts.length; i++) {
50+
var post = db.posts[i];
51+
if(post.id == post_id) {
52+
post.likes += delta;
53+
fs.writeFile(_this.path, JSON.stringify(db, undefined, 2), function(err, res) {
54+
if(err) throw err;
55+
if(callback) callback();
56+
});
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}
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}
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});
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}
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exports.JankyDB = JankyDB;

‎janky-blog/mv-posts.json‎

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{
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"latest_post_id": 2,
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"posts": [
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{
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"id": 0,
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"title": "Initial Post",
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"body": "Hello world",
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"likes": 10
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},
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{
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"id": 2,
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"title": "test",
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"body": "foo",
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"likes": 0
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},
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{
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"id": 3,
18+
"title": "Another post",
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"body": "fun timez",
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"likes": 0
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}
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]
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}

‎janky-blog/posts.json‎

Lines changed: 11 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,11 @@
1-
[
2-
{
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"title": "Initial Post",
4-
"body": "Hello world"
5-
},
6-
{
7-
"title": "test",
8-
"body": "foo"
9-
},
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{
11-
"title": "Another post",
12-
"body": "fun timez"
13-
}
14-
]
1+
{
2+
"next_post_id": 1,
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"posts": [
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{
5+
"title": "Foo",
6+
"body": "bar",
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"likes": 1,
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"id": 0
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}
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]
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}

‎janky-blog/public/jankyblog.js‎

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1+
document.addEventListener('DOMContentLoaded', function() {
2+
var like_buttons = document.querySelectorAll('a.like-button');
3+
for(var i=0; i < like_buttons.length; i++) {
4+
var like_button = like_buttons[i];
5+
install_like_handler(like_button);
6+
}
7+
});
8+
9+
function install_like_handler(like_button) {
10+
var post_id = like_button.dataset.postId;
11+
like_button.addEventListener('click', function() {
12+
var command;
13+
if(like_button.innerText == 'Like') {
14+
command = 'like';
15+
} else {
16+
command = 'unlike';
17+
}
18+
// AJAX magic!
19+
var req = new XMLHttpRequest();
20+
req.open('get', '/' + command + '/' + post_id, true); // e.g. /like/2
21+
req.addEventListener('load', function() {
22+
update_like_number(like_button)
23+
});
24+
req.send();
25+
});
26+
}
27+
28+
function update_like_number(like_button) {
29+
var liking = like_button.innerText == 'Like';
30+
if(liking) {
31+
like_button.innerText = 'Unlike';
32+
} else {
33+
like_button.innerText = 'Like';
34+
}
35+
var parent = like_button.parentElement;
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var counter_element = parent.querySelector('.likes-counter');
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var num_people = parseInt(counter_element.innerText);
38+
if(liking) {
39+
counter_element.innerText = (num_people + 1).toString();
40+
} else {
41+
counter_element.innerText = (num_people - 1).toString();
42+
}
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}

‎janky-blog/views/index.handlebars‎

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Original file line numberDiff line numberDiff line change
@@ -1,6 +1,7 @@
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<html>
22
<head>
33
<title>JankyBlog | View Posts</title>
4+
<script src="jankyblog.js"></script>
45
</head>
56
<body>
67
<h1>Awsum Blog</h1>
@@ -9,6 +10,10 @@
910
<div class="post">
1011
<h2>{{title}}</h2>
1112
<div class="post-body">{{body}}</div>
13+
<div class="likes">
14+
<span id="num-likes-{{id}}" class="likes-counter">{{likes}}</span> people like this.&nbsp;
15+
<a data-post-id="{{id}}" class="like-button" href="#">Like</a>
16+
</div>
1217
</div>
1318
{{/each}}
1419
</body>

‎janky-blog/web.js‎

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Original file line numberDiff line numberDiff line change
@@ -1,11 +1,10 @@
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// import needed libraries (installed with npm)
22
var express = require('express');
3-
var fs = require('fs');
43
var exphbs = require('express3-handlebars');
4+
var db = require('./jankydb');
55

66
var app = express();
7-
8-
var POSTS_FILE = 'posts.json';
7+
var db = new db.JankyDB('posts.json');
98

109
// detail, not sure why express does't do this automatically
1110
app.use(express.urlencoded());
@@ -15,11 +14,12 @@ app.use(express.logger());
1514
app.engine('handlebars', exphbs());
1615
app.set('view engine', 'handlebars');
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17+
// serve static files (jankyblog.js)
18+
app.use(express.static(__dirname + '/public'));
19+
1820
// tell express how to handle requests
1921
app.get('/', function(req, res) {
20-
fs.readFile(POSTS_FILE, function(err, contents) {
21-
if(err) throw err;
22-
var posts = JSON.parse(contents);
22+
db.getPosts(function(posts) {
2323
res.render('index', {posts: posts});
2424
});
2525
});
@@ -29,28 +29,32 @@ app.get('/write', function(req, res) {
2929
});
3030

3131
app.post('/save', function(req, res) {
32-
// load posts
33-
fs.readFile(POSTS_FILE, function(err, contents) {
34-
if(err) throw err;
35-
var posts = JSON.parse(contents);
36-
// construct our new post from data received in request
37-
var post = {
38-
title: req.body.title,
39-
body: req.body.body
40-
};
41-
// insert our new post
42-
posts.push(post);
43-
// serialize posts back to a string
44-
var serialized = JSON.stringify(posts, null, 2);
45-
// save posts with new one added
46-
fs.writeFile(POSTS_FILE, serialized, function(err) {
47-
if(err) throw err;
48-
console.log('posts saved');
49-
res.redirect('/'); // send user back to index
50-
});
32+
var post = {
33+
title: req.body.title,
34+
body: req.body.body,
35+
likes: 0
36+
};
37+
db.addPost(post, function() {
38+
console.log('posts saved');
39+
res.redirect('/'); // send user back to front page
40+
});
41+
});
42+
43+
app.get('/like/:post_id', function(req, res) {
44+
var post_id = req.params.post_id;
45+
db.changePostLikes(post_id, 1, function() {
46+
res.send(201);
47+
});
48+
});
49+
50+
app.get('/unlike/:post_id', function(req, res) {
51+
var post_id = req.params.post_id;
52+
db.changePostLikes(post_id, -1, function() {
53+
res.send(201);
5154
});
5255
});
5356

57+
// start it up
5458
app.listen(3000, function() {
5559
console.log('listening on http://localhost:3000/');
5660
});

‎timer.html‎

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