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tc39_study
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Daiki Ihara
October 09, 2019
Programming
1
760
tc39_study
Temporal
BinaryAST
Daiki Ihara
October 09, 2019
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Transcript
tc39_study https://github.com/sasurau4/slides
ABOUT ME { "id": "sasurau4", "name": "Daiki Ihara", "description": "Front-end engineer at CureApp, Inc.", "techs": { "work": ["React Native", "TypeScript", "JavaScript", "MongoDB"], "subwork": ["React Native", "React", "TypeScript"], "hobby": ["React", "TypeScript", "JavaScript", "Deno"] },
"homepage": "https://sasurau4.github.io/profile/" }
What is temporal? Provides standard objects and functions for working with dates and times. This proposal is currently stage 2.
Motivation Fixing JavaScript Date java.util.Date― その悲劇と歴史
Principles All temporal APIs are non-mutating. All temporal objects are effectively immutable. All date values are based on the Proleptic Gregorian Calendar. All time-of-day values are based on a standard 24-hour clock. Leap seconds are not represented.
Specification The documentation is out of date.
Try it with polyfill node --experimental-modules --no-warnings --icu-data-dir ./node_modules/full-icu/ -r ./lib/initialise.js For more details, https://github.com/tc39/proposal-temporal/tree/main/docs
Results > const day = Temporal.Date(2019, 1, 1) undefined > day.day 1 > day.toString() '2019-01-01'
> let d1 = Temporal.DateTime(2019, 2, 1) undefined > d1.toLocaleString() '2019/2/1 0:00:00' > d1.daysInMonth 28 > let onem = Temporal.Duration(0, 1) undefined > onem.toString() 'P1M'
What is binaryAST? Startup performance degrades with larger JS payloads, even if only a fraction of the code is actually executed. Parsing time is a significant component, taking more CPU time than bytecode / initial JIT code generation. For example, on a powerful laptop, Chrome spends 10% to 15% of CPU time parsing JS while loading facebook.com. We propose a new over-the-wire format for JS that is a binary encoding of an AST. We believe this new format would allow for drastically faster parsing. Moreover, web developers are well positioned to adopt a new format as they have embraced build tooling.
Motivation from https://blog.cloudflare.com/binary-ast/
prototype of binAST from https://github.com/binast/binjs-ref As websites become more sophisticated, the amount of JavaScript source code keeps increasing. While depending upon a large JavaScript codebase won't prevent a website from working, it will cause websites to start slowly – often unacceptably slow. This is due to two bottlenecks: parsing and bytecode compiling JavaScript. Unfortunately, browsers have pretty much reached efficiency peak for both operations. We (Mozilla, Bloomberg, Facebook,
CloudFlare) are currently working on a domain-specific encoding for JavaScript, called "BinAST" (short for "JavaScript Binary AST"). The JavaScript Binary AST is designed to break the bottleneck.
Result
Details https://blog.cloudflare.com/binary-ast/
Demo Try it with Firefox nightly! https://serve-binjs.that-test.site
The End