November January 20223 TC39 Champion: Shu-yu Guo (Google) Authors: Santiago Díaz (Google), Jun Kokatsu (Google)
The changes of proposal’s status @ 93th meeting of Ecma TC39 ECMA-262 New Proposals Proposal Stage
はじめに 個人的に TC39 meeting をウォッチしてまとめている @petamoriken です。 ECMAScript の Decorators の提案は何度も改定しています。その割にあまり知れ渡っていません。この記事ではその変遷と最終的な Decorators の仕様について簡単にまとめようと思います。 この発表スライドを見ると流れがわかりやすいかもしれません。 最初の提案(2014年~2015年頃) 最初の提案はこのような形式をしていました。 class Person { @nonenumerable get kidCount() { return this.children.length; } } function nonenumerable(target, name, description) { descriptor.enumerable = false; return
More information on the syntax and semantics of decorators (optional section) # (This section is optional. If you skip it, you can still understand the remaining content.) The syntax of decorator expressions # A decorator expression starts with a chain of one or more identifiers, separated by dots. Each identifier except the first one can be private (prefix #). Square brackets [] are not allowed
Let us consider a few scenarios from the real world to understand what we are trying to solve in this proposal. On MouseEvent we are interested on 'ctrlKey', 'shiftKey', 'altKey', 'metaKey' events only. We have a configObject and we need ['dependencies', 'devDependencies', 'peerDependencies'] from it. We have an optionsBagand we would allow on ['shell', 'env', 'extendEnv', 'uid', 'gid'] on it. Fro
There were several items on the agenda, this post focuses on feature proposals and their progress from the meeting that was held between 19-21st July 2022. Stage 4: Hashbang Grammar: match de-facto usage in some CLI JS hosts that allow for #! Shebangs / Hashbang. Stage 3: Duplicate named capturing groups: allow regex capturing group names to be repeated. Stage 2: Import Reflection: Proposal for sy
この記事では2022年06月06日~09日に開催された TC39 meeting 90th で議題に上がったプロポーザルを紹介します。 For Stage 4 findLast / findLastIndex Stage 4 に到達しました findLast と findLastIndex は、Array.prototype.find と Array.prototype.findIndex の逆から走査するバージョンです。 const arr = [ { prop1: 1, prop2: "foo" }, { prop1: 1, props2: "bar" }, ]; const obj1 = arr.find((element) => element.prop1 === 1); console.log(obj1.prop2); // "foo" const obj2 = arr.find
(This blog post is based on a tweet thread and additional input by Mathias Bynens.) After work started on it in August 2017, May 2022 finally saw the publication of RFC 9239 “Updates to ECMAScript media types” by Matthew A. Miller, Myles Borins, Mathias Bynens, and Bradley Farias. It updates JavaScript MIME type registrations to align with reality: The JavaScript MIME type is now unambiguously tex
Announced May 20, 2022 Impact critical Products Firefox, Firefox ESR, Firefox for Android, Thunderbird Fixed in Firefox 100.0.2 Firefox ESR 91.9.1 Firefox for Android 100.3 Thunderbird 91.9.1 #CVE-2022-1802: Prototype pollution in Top-Level Await implementation Reporter Manfred Paul via Trend Micro's Zero Day Initiative Impact critical Description If an attacker was able to corrupt the methods of
Today we’re excited to announce our support and collaboration on a new Stage 0 proposal to bring optional and erasable type syntax to JavaScript. Because this new syntax wouldn’t change how surrounding code runs, it would effectively act as comments. We think this has the potential to make TypeScript easier and faster to use for development at every scale. We’d like to talk about why we’re pursuin
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