Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
jQuery Deferreds and Promises
Search
Eli Perelman
November 01, 2011
Technology
10
360
jQuery Deferreds and Promises
My introduction slides from the Omaha Front-end Web and jQuery meetup on November 1, 2011.
Eli Perelman
November 01, 2011
Tweet
Share
More Decks by Eli Perelman
See All by Eli Perelman
Intro to Raptor
eliperelman
0
120
UI Synchronicity
eliperelman
1
130
Other Decks in Technology
See All in Technology
エンジニアリングマネージャーの成長の道筋とキャリア / Developers Summit 2025 KANSAI
daiksy
3
1k
Oracle Base Database Service 技術詳細
oracle4engineer
PRO
10
75k
DroidKaigi 2025 Androidエンジニアとしてのキャリア
mhidaka
2
380
TS-S205_昨年対比2倍以上の機能追加を実現するデータ基盤プロジェクトでのAI活用について
kaz3284
1
220
AIエージェント開発用SDKとローカルLLMをLINE Botと組み合わせてみた / LINEを使ったLT大会 #14
you
PRO
0
130
Modern Linux
oracle4engineer
PRO
0
160
使いやすいプラットフォームの作り方 ー LINEヤフーのKubernetes基盤に学ぶ理論と実践
lycorptech_jp
PRO
1
150
S3アクセス制御の設計ポイント
tommy0124
3
200
[ JAWS-UG 東京 CommunityBuilders Night #2 ]SlackとAmazon Q Developerで 運用効率化を模索する
sh_fk2
3
460
「全員プロダクトマネージャー」を実現する、Cursorによる仕様検討の自動運転
applism118
22
12k
5分でカオスエンジニアリングを分かった気になろう
pandayumi
0
260
Apache Spark もくもく会
taka_aki
0
140
Featured
See All Featured
Intergalactic Javascript Robots from Outer Space
tanoku
272
27k
Done Done
chrislema
185
16k
個人開発の失敗を避けるイケてる考え方 / tips for indie hackers
panda_program
113
20k
For a Future-Friendly Web
brad_frost
180
9.9k
CoffeeScript is Beautiful & I Never Want to Write Plain JavaScript Again
sstephenson
162
15k
The Myth of the Modular Monolith - Day 2 Keynote - Rails World 2024
eileencodes
26
3k
Stop Working from a Prison Cell
hatefulcrawdad
271
21k
The Cult of Friendly URLs
andyhume
79
6.6k
Creating an realtime collaboration tool: Agile Flush - .NET Oxford
marcduiker
31
2.2k
Git: the NoSQL Database
bkeepers
PRO
431
66k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
333
22k
Building a Modern Day E-commerce SEO Strategy
aleyda
43
7.6k
Transcript
jQuery Deferreds & Promises Eli Perelman @eliperelman
What are deferreds?
Provide a system to register callbacks into neatly managed queues
DEFERREDS
WITHOUT DEFERREDS var validateUser = function ( username, password, callback
) { if ( username === ‘bob’ && password === ‘123’ ) { callback( ‘success’ ); } else { callback( ‘failure’ ); } }; validateUser( ‘bob’, ‘123’, function ( result ) { if ( result === ‘success’ ) { location = ‘/dashboard’; } else { showError( ‘Invalid login.’ ); } });
WITH DEFERREDS var validateUser = function ( username, password )
{ var deferred = $.Deferred(); if ( username === ‘bob’ && password === ‘123’ ) { deferred.resolve(); } else { deferred.reject(); } return deferred.promise(); }; validateUser( ‘bob’, ‘123’ ) .done( function () { location = ‘/dashboard’; }) .fail( function () { showError( ‘Invalid login.’ ); });
Deferreds work with synchronous AND asynchronous functions.
Since jQuery 1.5, the $.ajax module uses deferreds.
What are promises?
Provide a common API for consuming code to register callbacks,
sync or async. PROMISES
Deferreds Promises .then .then .done .done .fail .fail .always .always
.reject .resolve .pipe .pipe .promise .promise .isResolved .isRejected
Coding time!