Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.

This is the legacy version of twitter.com. We will be shutting it down on June 1, 2020. Please switch to a supported browser, or disable the extension which masks your browser. You can see a list of supported browsers in our Help Center.

  • Home Home Home, current page.
  • About

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
mathias's profile
Mathias Bynens
Mathias Bynens
Mathias Bynens
Verified account
@mathias

Tweets

Mathias BynensVerified account

@mathias

I work on @ChromeDevTools & @v8js at Google and on ECMAScript through TC39. ♥ JavaScript, HTML, CSS, HTTP, performance, security, Bash, Unicode, i18n, macOS.

Munich, Germany
mths.be
Joined January 2007

Tweets

  • © 2020 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Imprint
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. V8‏Verified account @v8js 13 Sep 2018
      • Report Tweet
      • Report NetzDG Violation

      🔥 Jest reduced their test runner time by 20% by switching from plain JavaScript objects to Maps where it made sense. https://github.com/facebook/jest/pull/6960 … In general, don’t be afraid to use modern features! Focus on writing idiomatic code, and let JS engines worry about making it fast.

      5 replies 218 retweets 642 likes
    2. Geordie Powers‏ @GeordiePowers 13 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @v8js

      I've always avoided maps because I read long ago that they're the wrong tool for pretty much any job, clearly that's wrong. Where DO they make sense? What are some cases they perform better in? (Alternatively, what made it the right choice for Jest?)

      3 replies 0 retweets 1 like
      Mathias Bynens‏Verified account @mathias 13 Sep 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @GeordiePowers

      Whenever you need the concept of a lookup table without the need to walk up the prototype chain for missing properties, use a map, not an object.

      8:02 AM - 13 Sep 2018
      • 5 Retweets
      • 25 Likes
      • Daniel E Philipp Renoth 🇩🇪🍻 Jakub Beránek kolombet dontry Karan Andy Van Slaars leeight Tim van der Lippe
      4 replies 5 retweets 25 likes
        1. New conversation
        2. Rob Palmer‏ @robpalmer2 13 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @mathias @GeordiePowers

          Does this advice still apply if you have thousands of tables with few or zero items in each table?

          1 reply 0 retweets 0 likes
        3. Mathias Bynens‏Verified account @mathias 14 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @robpalmer2 @GeordiePowers

          Yes. Why wouldn’t it?

          1 reply 0 retweets 0 likes
        4. 1 more reply
        1. New conversation
        2. Frank Wallis‏ @frankwallis 13 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @mathias @GeordiePowers

          ...as long as you don't need to serialize it.

          1 reply 0 retweets 1 like
        3. Rubén Norte‏ @RubenNorte 13 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @frankwallis @mathias @GeordiePowers

          We do serialize it and it's even faster than serializing objects. The hidden trick is that we use v8 serialization (read&written using Node) instead of JSON.

          0 replies 0 retweets 7 likes
        4. End of conversation
        1. Jacob 'KurtXTRM' Groß‏ @kurtextrem 14 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @mathias @GeordiePowers

          I'd add "if you don't need to clone them" - which is way slower using Maps: https://esbench.com/bench/5b9b70d4f2949800a0f62058 …

          0 replies 0 retweets 1 like
          Thanks. Twitter will use this to make your timeline better. Undo
          Undo
        1. New conversation
        2. Keith Cirkel‏ @Keithamus 14 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @mathias @GeordiePowers

          How does that compare to Object.create(null)?

          1 reply 0 retweets 0 likes
        3. Keith Cirkel‏ @Keithamus 14 Sep 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @Keithamus @mathias @GeordiePowers

          Keith Cirkel Retweeted Jason Williams

          Ah, I should have RTFPR, because it jest were using Object.create(null), as @Jason_williams mentionshttps://twitter.com/Jason_williams/status/1040512363198328832?s=19 …

          Keith Cirkel added,

          Jason Williams @Jason_williams
          Replying to @KarimSaNet @v8js
          Jest were doing exactly that, creating an object with null for prototype and there were still performance gains. My guess is because Objects can do a lot, so they come with a lot of overhead, Maps are pretty lightweight, so V8 can optimise them well.
          0 replies 0 retweets 0 likes
        4. End of conversation

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2020 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Imprint
        • Cookies
        • Ads info