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
Practically Immutable
Search
sporto
March 28, 2015
Technology
0
190
Practically Immutable
Immutable data in practice in JavaScript
sporto
March 28, 2015
Tweet
Share
More Decks by sporto
See All by sporto
React inside Elm
sporto
2
180
Elm
sporto
1
250
Redux: Flux Reduced
sporto
1
330
Webpack and React
sporto
4
380
Rails with Webpack
sporto
1
220
Lesson learnt building Single Page Application
sporto
0
120
Grunt
sporto
1
180
Safe Testing in Ruby
sporto
1
130
Go - A great language for building web applications
sporto
1
340
Other Decks in Technology
See All in Technology
Rustから学ぶ 非同期処理の仕組み
skanehira
1
150
20250910_障害注入から効率的復旧へ_カオスエンジニアリング_生成AIで考えるAWS障害対応.pdf
sh_fk2
3
260
DroidKaigi 2025 Androidエンジニアとしてのキャリア
mhidaka
2
380
AIエージェントで90秒の広告動画を制作!台本・音声・映像・編集をつなぐAWS最新アーキテクチャの実践
nasuvitz
3
320
下手な強制、ダメ!絶対! 「ガードレール」を「檻」にさせない"ガバナンス"の取り方とは?
tsukaman
2
450
Create Ruby native extension gem with Go
sue445
0
100
AIをプライベートや業務で使ってみよう!効果的な認定資格の活かし方
fukazawashun
0
100
現場で効くClaude Code ─ 最新動向と企業導入
takaakikakei
1
260
Agile PBL at New Grads Trainings
kawaguti
PRO
1
450
研究開発と製品開発、両利きのロボティクス
youtalk
1
530
品質視点から考える組織デザイン/Organizational Design from Quality
mii3king
0
210
「その開発、認知負荷高すぎませんか?」Platform Engineeringで始める開発者体験カイゼン術
sansantech
PRO
2
130
Featured
See All Featured
How To Stay Up To Date on Web Technology
chriscoyier
790
250k
Rebuilding a faster, lazier Slack
samanthasiow
83
9.2k
Stop Working from a Prison Cell
hatefulcrawdad
271
21k
The MySQL Ecosystem @ GitHub 2015
samlambert
251
13k
The Art of Delivering Value - GDevCon NA Keynote
reverentgeek
15
1.7k
Building a Scalable Design System with Sketch
lauravandoore
462
33k
Music & Morning Musume
bryan
46
6.8k
Producing Creativity
orderedlist
PRO
347
40k
Optimising Largest Contentful Paint
csswizardry
37
3.4k
Evolution of real-time – Irina Nazarova, EuRuKo, 2024
irinanazarova
8
920
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
656
61k
Visualization
eitanlees
148
16k
Transcript
practically immutable ! Immutable data in JS @sebasporto
I build CRUD apps, mostly
What? • Something that cannot change • Once created stays
the same
var array1 = [1, 2].immutable var array2 = array1.push(3) !
array1 //=> [1, 2] array2 //=> [1, 2, 3]
WHY?
# 1 no side effects
var orders = [1, 2]; processOrders(orders); what is orders after
this?
Predictability Store Comp Comp Data Data wants to sort data
wants to transform data doesn't want its data to be modified externally
Enforces uni directional data flow React + Flux Store Comp
Action
# 2 Easier workflows
Undo add(item) { history.push(items) items = items.push(item) } undo() {
items = history.pop() }
Dirty objects Get record from store Clone record Edit record
Save Replace original Yes Discard No
Dirty objects Get record from store Edit record Save Replace
original Yes Discard No
HOW?
clojurescript immutable data for free but this talk is about
plain JS
• In JS strings and numbers are immutable (not the
case in every language) • Arrays, objects are not - so we need help here • JS and immutable data => opposing forces
immutable.js • Great for simple collections • [1, 2, ...]
['a', 'b' ...] • Caveats for collections with objects https://github.com/facebook/immutable-js
Immutable.js var record = {label: 'Sam'}; var list = Immutable.List([record]);
! console.log(list.get(0).label) // => 'Sam' http://jsbin.com/dilupu/1/embed?js,console record.label = 'Biff' ! console.log(list.get(0).label) // => 'Biff' Opps!
immutable.js To be fair: Immutable.js can do the right thing
if you learn it really well Immutable.js != Just works™
Seamless immutable • Fixes Immutable.js issues with deep objects https://github.com/rtfeldman/seamless-immutable
var record = {label: 'Sam'}; var list = Immutable([record]); !
console.log(list[0].label) // => 'Sam' ! record.label = 'Biff' ! console.log(list[0].label) // => 'Sam' http://jsbin.com/fayupu/1/edit?js,console Seamless immutable
imm https://github.com/sporto/imm • Build on top of seamless-immutable • Nice
CRUD API
imm list = list.add(record) list = list.replace(record) list = list.remove(id)
! record = list.get(id)
in Conclusion
Immutable data can make your application more robust
but play a lot with your chosen lib, understand
the caveats
Thanks