자바스크립트 스터디

A Tale of TurboFan: Four years that changed V8 forever

Inlining

Escape Analysis and Scalar Replacement

Making WebAssembly even faster: Firefox's new streaming and tiering compiler

Streaming compilation : Tier 1(or baseline compiler) and Tier 2 compiler

New bottleneck: CPU - main thread

Caching .wasm file

The Cost Of JavaScript

Bottleneck = Network(transmission size) + CPU(parse time)

JavaScript Startup Bytecode Cache

Optimizing hash tables: hiding the hash code

private symbol을 사용 -> symbol lookup이 필요

Backing store를 사용 -> lookup이 필요없게 되었다. 성능 향상!
: empty, array, dictionary

Fast Properties in V8

Named properties vs Indexed properties

Hidden classes and Descriptor arrays

In-object, fast, slow

Explaining JavaScript VMs in JavaScript - Inline Cached

Must-Watch JavaScript

In The Loop

Tasks - Animation callbacks - Microtasks

Tasks: 한번에 하나만 실행
Animation callbacks: 실행 시점에 큐에 있는 것은 모두 실행(실행 중 추가된 콜백은 다음번에 실행)
Microtasks: 큐가 빌때까지 계속 실행(따라서, 무한히 실행하는 것에 주의 필요)

자바스크립트와 이벤트 루프

Tasks, microtasks, queues and schedules

How JavaScript Timers Work

setTimeout vs setInterval

setInterval : 큐에 이전 핸들러가 실행되지 못하고 남아 있으면 새로 추가하지 않는다.

Elements kinds in V8

small integer -> PACKED_SMI_ELEMENTS
floating-point number -> PACKED_DOUBLE_ELEMENTS
regular element(string) -> PACKED_ELEMENTS

from PACKED to HOLEY

Avoid creating holes
Avoid reading beyond the length of the array
Avoid elements kind transitions
Prefer arrays over array-like objects
Avoid polymorphism

Bubbling and capturing

A cartoon guide to Flux

Kotlin 스터디

KotlinConf 2017

* Introduction to Coroutines *

https://resources.jetbrains.com/storage/products/kotlinconf2017/slides/2017+KotlinConf+-+Introduction+to+Coroutines.pdf

- Synchronous
- Asynchronous

-> Callback

- Futures/Promises/Rx

-> returns promise for a future result immediately

- Coroutines

-> suspend: returns result when received
-> like regular code

- Coroutines are like very light-weight threads

http://github.com/kotlin/kotlinx-coroutines

* Deep Dive into Coroutines on JVM *

https://resources.jetbrains.com/storage/products/kotlinconf2017/slides/2017+KotlinConf+-+Deep+dive+into+Coroutines+on+JVM.pdf

- Continuation Passing Style(CPS)

-> Callback

- State Machine

- Communicating Sequential Processes(CSP)

* Kotlin Types: Exposed *

Int vs Int?

IntArray vs Array<Int>

Any vs Object

Boxing under the hood vs No boxing

Unit vs Nothing vs void

Unit

-> a type that allows only one value and thus can hold no information
-> the function completes successfully

Nothing :

-> a type that has no values
-> It means "this function never returns"

- Unit과 Nothing은 Kotlin에서 위와 같은 차이가 있지만 JVM에서 똑같이 void로 컴파일된다.

Nothing?

@Nullable -> Type? and @NotNull(@NonNull) -> Type

How to still prevent NPEs? - 자바 코드를 코틀린에서 사용하는 경우 문제가 발생

-> Annotate your Java types

compileKotlin {
  kotlinOptions {
    freeCompilerArgs += "-Xjsr305=strict"
  }
}

-> Specify types explicitly

Collections

-> Read-only : it is not immutable
-> Mutable

* Generating Kotlin Code *

KotlinPoet

A Functional Approach to Android Architecture using Kotlin

- Modeling Error and Success Cases

-- Result wrapper(Error or Success)
-- RxJava
-- KATEGORY

- Asynchronous Code and Threading

-- Java : ThreadPoolExecutor + exceptions + callbacks
-- RxJava : Schedulers + observable + error subscription
-- KATEGORY

Lazy evaluation

- Dependency Injection

-- Reader Monad: ReaderT, Monad Transformers

Exploring Kotlin's hidden costs - Part 1

Coroutine Theory

- Normal function

Call/Return

activation frame(stack)

- Coroutine

Suspend/Resume/Destroy

coroutine frame(heap) and stack frame

Kotlin Coroutines on Android: Things Wish I Knew at the Beginning

- Executor를 CoroutineDispatchers로 바꿀 수 있다.

- RxJava의 disposable 같은 것을 위해 "root" coroutine parent를 사용할 수 있다.

- CommonPool 의 크기를 조절할 수 있다.

- Async에서의 exception은 바로 발생되지 않는다.

- coroutine들을 협력적으로 cancel 하려면 CoroutineContext를 통한 parent-child 관계가 필요하다.

Async code using Kotlin Coroutines

RxJava to Kotlin coroutines

코루틴과 관련해서 Continuation에 대해서도 알면 좋을것 같다.

What's in a Continuation

Implementing a Stepping Debugger in JavaScript

Exploring Continuations: Resumable Exceptions

Swift 스터디 - Sequence, Pointer types

Conditional Conformance in the Standard Library

Equatable Containers

Collection Protocols

Swift의 Sequence와 Collection에 대해 알아야 하는것들

https://academy.realm.io/kr/posts/nate-cook-tryswift-tokyo-unsafe-swift-and-pointer-types/

https://academy.realm.io/posts/mobilization-roy-marmelstein-objective-c-runtime-swift-dynamic/

Type-Safe File Paths with Phantom Types

Rust 스터디

https://cfsamson.gitbook.io/green-threads-explained-in-200-lines-of-rust/

Zero-cost futures in Rust

Designing futures for Rust

https://blog.rust-lang.org/2015/04/10/Fearless-Concurrency.html

https://blog.rust-lang.org/2015/05/11/traits.html

http://huonw.github.io/blog/2015/05/finding-closure-in-rust/

https://alschwalm.com/blog/static/2017/03/07/exploring-dynamic-dispatch-in-rust/

http://huonw.github.io/blog/2015/01/peeking-inside-trait-objects/

안드로이드 스터디

The Dex File Format

.java -> .class -> .dex

ART: Ahead-of-Time and Just-in-Time

D8, R8

Sinking Your Teeth Into Bytecode

sources + libraries -> compilers -> transforms -> d8 -> *.dex -> ART(Interperter, JIT, AOT) -> Machine code

- 리스트에 비디오 플레이 넣기

한번에 하나만 플레이 하도록 하기 위해 리스트 아이템 사이에 정보 전달이 필요하다.

https://medium.com/@v.danylo/implementing-video-playback-in-a-scrolled-list-listview-recyclerview-d04bc2148429

- RecyclerView는 어떻게 구현되어 있을까?

RecyclerView ins and outs - Google I/O 2016

http://blog.naver.com/PostList.nhn?from=postList&blogId=mail1001&categoryNo=14&currentPage=4

It's time to ditch Loaders in Android

Loader는 이제 그만.
Architecture Components를 사용하자.

안드로이드 스터디 - UI

Playing with Paths

- Cartesian coordinates vs polat coordinates
- Path, CornerPathEffect, DashPathEffect

https://gist.github.com/nickbutcher/b41da75b8b1fc115171af86c63796c5b#file-polygonlapsdrawable-kt

Understanding Android Adaptive Icons

Designing Adaptive Icons

Implementing Adaptive Icons

VectorDrawable Adaptive Icons

- What is WindowInsets?

Becoming a master window fitter

Spantastic text styling with Spans

SpannedString
SpannableString
SpannableStringBuilder

Appearance Affecting Spans vs Metric Affecting Spans

Character Affecting Spans vs Paragraph Affecting Spans

CharacterStyle
ParagraphStyle
UpdateAppearance
UpdateLayout