Functionality Focused Code Organization

Functionality-Focused Code Organization
Rebecca Murphey • @rmurphey • rebeccamurphey.com
jQuery Boston 2010

Saturday, October 16, 2010

object laterals literals
module pattern
revealing module pattern
etc.


$('#search').submit(function(e) {
e.preventDefault();
resultsContainer.empty();

var term = $(this).find('input').val();
if (!$.trim(term)) { return; }

$.each(['search.news', 'search.web'], function(i, svcName) {
$.getJSON(
searchUrl,
{ q : buildQuery(term, svcName), format : 'json' },

function(resp) {
$('<li><h3>' + svcName + '</h3><ul></ul></li>')
.appendTo(resultsContainer)
.find('ul')
.html(
$.map(resp.query.results.result, function(r) {
return Mustache.to_html(resultsTpl, r);
}).join('')
);
}
);
});
});

a “traditional” jQuery way of solving the problem

what happens when the spec evolves?


is the codebase suitable for collaboration?


e.preventDefault();


$.getJSON(
searchUrl,

function(resp) {
.find('ul')
.html(
}).join('')
);
}
);
});
});


is it testable?


e.preventDefault();


$.getJSON(
searchUrl,

function(resp) {
.find('ul')
.html(
}).join('')
);
}
);
});
});

how to test all of the important pieces of this?

is it readable & maintainable?


“Writing to be read means writing code ... with
the idea that someone else will read it. is fact
alone will make you edit and think of better
ways to solve the problem you have at hand.”
Stoyan Stefanov, “JavaScript Patterns”


maintainable code is ...
readable
consistent
predictable
looks like one person wrote it
documented


// NAVIGATION
function togglePage(section) {
// if the clicked section is already the current section AND we're in full page mode
// minimize the current tab
if (jQuery('#md_tab_'+ section).hasClass('current') && jQuery('#md_tab_'+ section + ' a').hasClass('md_fullpage')) {
// alert('clicked section is current section AND fullpage mode is active; teaser should load');
// Minimize
jQuery('#md_tabs_navigation a').removeClass('md_fullpage');
jQuery('.md_body').hide();
jQuery('#md_feature').slideDown('normal',function(){
var bodyContent = jQuery('#md_body_'+ section);
bodyContent.fadeOut('normal',function(){
jQuery('#md_tabs_navigation a').each(function(){
var thisSection = jQuery(this).html().replace('<span<','').replace('</span<','');
var thisSection_comp = thisSection.toLowerCase().replace(' ','_');
jQuery('#md_body_'+ thisSection_comp).load(
'/app/modules/info/loadTeaser.php?sect='+ thisSection_comp,
function(){
tb_init('.md_body a.thickbox, .md_body area.thickbox, .md_body input.thickbox');
bodyContent.animate({ height: 'toggle', opacity: 'toggle' },"slow");
}
);
});
});
});
jQuery('#expandtabs span').empty().append('Expand Tabs');
} else {
// if the clicked section is NOT the current section OR we're NOT in full page mode
// then let's go to full page mode and show the whole tab
// Maximize
// alert('clicked section is not the current section OR full page mode is not active; full section should load');
jQuery('#md_tabs_navigation li').removeClass('current');
jQuery('#md_tab_'+ section).addClass('current');
jQuery('#md_tabs_navigation a').addClass('md_fullpage');
jQuery('.md_body').hide();
jQuery('#md_feature').slideUp('normal',function(){
var bodyContent = jQuery('#md_body_'+ section);
bodyContent.fadeOut('normal',function(){
bodyContent.empty();
var pageLoader = 'info/loadSection.php?sect='+ section;
if (section == 'contact_us') {
pageLoader = 'contact/loadContactForm.php?form_id=1';
}
bodyContent.load('/app/modules/'+ pageLoader,function(){
// ADD THICKBOXES
tb_init('.md_body a.thickbox, .md_body area.thickbox, .md_body input.thickbox');
$recent_news_links = jQuery('ul.md_news li a.recent_news_link');
$recent_news_links
.unbind('click')
.each(function(){
var hrefMod = this.href;
hrefMod = hrefMod.replace(/article/,'loadNews').replace(/storyid/,'id');
this.href = hrefMod;
})
.click(function(){
var t = this.title || this.name || null;
var a = this.href || this.alt;
var g = this.rel || false;
tb_show(t,a,g);
this.blur();
return false;
Saturday, October 16, 2010 });

(By the way, buy this book.)


When the heavy lifting of manipulating,
displaying, and interacting with data falls
to the browser, it makes sense to reconsider
the typical DOM-centric approach.


there’s a better way*
*lots of them, in fact. this is one.


Functionality-focused code organization
means identifying the pieces of functionality in
your application and teasing them apart.


diversion: pubsub 101
like custom events, but without the overhead!


$('input.magic').click(function(e) {
// publish a "topic" when something happens
$.publish('/something/interesting', [ e.target.value ]);
});

// register our interest in knowing when something happens
$.subscribe('/something/interesting', function(val) {
alert(val);
});

a simple pubsub example

$('input.magic').click(function(e) {
$(document).trigger('/something/interesting', [ this.value ]);
});

$(document).bind('/something/interesting', function(e, val) {
alert(val);
});

pubsub with custom events works too

In jQuery itself, $.fn.ajaxStart and
$.fn.ajaxStop basically let you subscribe to
topics published by jQuery’s underlying
Ajax code.


diversion: require.def
possibly my new favorite thing
(also a great tool for this modularization stuﬀ)


require.def() De nes a function to be run
when the module is included. e function can
return a value, but it doesn’t have to. If
dependencies are speci ed, they’re available to
the function as arguments.


pattern: object Returns an object, though
the de nition function can close other
variables that won’t be visible outside the
function.


require.def(function() {
var privateThing = 'myPrivateThing',

privateObj = {
maxLength : 5,

setPrivateThing : function(val) {
if (val.length > this.maxLength) {
console.log('TOO MUCH');
return;
}

privateThing = val;
},

otherMethod : function() {
console.log(privateThing);
}
};

return {
setPrivateThing : $.proxy(privateObj, 'setPrivateThing'),
publicMethod : $.proxy(privateObj, 'otherMethod')
};
});

closes private vars, returns a public API

pattern: factory Returns a function, that,
when called, returns an instance of an object
that is de ned inside the module. e factory
function may optionally bake in instance
property options or overrides. e base object
is not exposed publicly.


require.def(function(){
var Person = {
intro : 'My name is ',
outro : '. You killed my father. Prepare to die.',

speak : function() {
console.log(
this.intro,
this.firstName,
this.lastName,
this.outro
);
}
};

return function(config) {
return $.extend(Object.create(Person), {
firstName : config.firstName,
lastName : config.lastName
});
};
});

returns a “factory” for creating Person instances

mediators
views
services


• user submits
search input search form
• user input is
validated
• if input is valid,
the search service is
searcher
contacted

searcher • when the search
service returns
results, they are
displayed in the
results container

results


• sets up views and services
search input view • brokers communication
between views and services
• sets up search input form
• listens for user to submit
search form search page
• veriﬁes form data
mediator
• announces the user’s search
if it is valid (non-empty)

results view
• provides an API for
mediators to add results and
clear the results container
• listens for user interaction
with results and broadcasts
searcher service results service
information about it to be
handled by the mediator • provides an API for
searcher service mediators to use to register
user interaction with results,
and to get information about
• provides an API for those interactions later
mediators to communicate
with
• performs searches and pre-
processes results into a
consistent format
• accepts callback to allow
results to be used by mediator


mediators set up views and services, and
broker communications between them,
eliminating the need for direct communication


views display data, observe user input, and
broadcast messages that mediators can react
to; may also provide an API for updating data


views in our sample application

services manage data & state, exposing a
limited public API for mediators


user requests page

app mediator

app mediator hands
request to appropriate
page mediator

page mediator sets up page mediator
views that will be required
for the page

page mediator sets up
services that will be required
for the page
views and services
DO NOT communicate
directly

view service

view service

view service


sample app
http://github.com/rmurphey/ﬀco


mediators
app mediator, page mediator
views
message, recent searches, search input, results
services
searchers, results


MOAR FEATURES PLZ?
indicate search term in URL
persist recent searches across page reloads
tabbed search results view
improve the code I didn’t show you


rebeccamurphey.com

blog.rebeccamurphey.com

@rmurphey

http://github.com/rmurphey/ﬀco

http://spkr8.com/t/4650

http://pinboard.in/u:rmurphey/t:ﬀco/


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