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﹃2ality – JavaScript and more﹄
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人気
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新着
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すべて
4users
2ality.com
Ecma International approves ECMAScript 2024: What’s new? On 26 June 2024, the 127th Ecma General Assembly approved the ECMAScript 2024 language specification, which means that it’s officially a standard now. This blog post explains what’s new. The editors of ECMAScript 2024 # The editors of this release are: Shu-yu Guo Michael Ficarra Kevin Gibbons What’s new in ECMAScript 2024? # Grouping synch
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テクノロジー
●2024/06/27 09:16
●article
●JavaScript
2users
2ality.com
ECMAScript 2024 features: resizing and transferring ArrayBuffers In this blog post, we examine ArrayBuffer features that were introduced in ECMAScript 2024: “In-place resizable ArrayBuffers”, proposed by Shu-yu Guo “ArrayBuffer.prototype.transfer and friends” proposed by Shu-yu Guo, Jordan Harband and Yagiz Nizipli What are ArrayBuffers? # The following classes provide an API for handling binary
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世の中
●2024/06/01 22:30
3users
2ality.com
In this blog post, we take a look at the ECMAScript 2023 feature “Symbols as WeakMap keys” – which was proposed by Robin Ricard, Rick Button, Daniel Ehrenberg, Leo Balter, Caridy Patiño, Rick Waldron, and Ashley Claymore. What are WeakMaps good for? # The key ability of a WeakMap is to associate data with a value: The value is the key of a WeakMap entry. The data is the value of that entry. Consi
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テクノロジー
●2024/05/21 22:25
●ECMAScript
2users
2ality.com
In this blog post we take a look at the ECMAScript 2024 feature “Promise.withResolvers” (proposed by Peter Klecha). It provides a new way of directly creating Promises, as an alternative to new Promise(...). new Promise(...) – the revealing constructor pattern # Before Promise.withResolvers(), there was only one way to create Promises directly – via the following pattern: const promise = new Prom
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テクノロジー
●2024/05/15 07:35
2users
2ality.com
In this blog post, we examine the ECMAScript proposal “Set methods for JavaScript” by Michał Wadas, Sathya Gunasekara and Kevin Gibbons. It introduces new methods for Sets. New Set methods that return Sets # set.union(other) # This method returns a Set that is the union of this and other. Type signature: Set<T>.prototype.union(other: SetReadOperations<T>): Set<T> The type of other, SetReadOperat
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テクノロジー
●2022/12/15 08:54
●javascript
3users
2ality.com
Update 2022-12-15: New section “How will this proposal affect future JavaScript APIs?” In this blog post, we look at the ECMAScript proposal “Iterator helpers” by Gus Caplan, Michael Ficarra, Adam Vandolder, Jason Orendorff, Kevin Gibbons, and Yulia Startsev. It introduces utility methods for working with iterable data: .map(), .filter(), .take(), etc. The style of the proposed API clashes with th
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テクノロジー
●2022/12/10 09:37
●proposal
●ECMAScript
●JavaScript
●article
3users
2ality.com
This blog post is about the ECMAScript proposal “Array.fromAsync for JavaScript” by J. S. Choi. It introduces a static method for converting asynchronous iterables to Arrays. Tools for working with synchronous iterables # Currently JavaScript provides several tools for working with synchronous iterables – for example: function* createSyncIterable() { yield 'a'; yield 'b'; yield 'c'; } // Array-de
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テクノロジー
●2022/11/28 09:00
●proposal
●ECMAScript
6users
2ality.com
ECMAScript proposal: RegExp flag /v makes character classes and character class escapes more powerful In this blog post, we look at the ECMAScript proposal “RegExp v flag with set notation + properties of strings” by Markus Scherer and Mathias Bynens. The new flag /v # The proposed new regular expression flag /v (.unicodeSets) enables three features: Support for multi-code-point graphemes (such a
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テクノロジー
●2022/11/19 10:11
●ECMAScript
●proposal
●unicode
●javascript
●article
●あとで読む
2users
2ality.com
Update 2022-11-05: More information on searching, finding accounts, being found, direct messages, etc. I use both Twitter and Mastodon and like both. Both have pros and cons. In this blog post, I’d like to explain how to get started with Mastodon. How is Mastodon different from Twitter? # Mastodon works more like email # Mastodon is similar to email: To join Mastodon, you need to find a server a
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テクノロジー
●2022/10/29 10:19
●article
9users
2ality.com
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
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テクノロジー
●2022/10/19 07:11
●javascript
●ECMAScript
●article
3users
2ality.com
Warning: This blog post is outdated. Instead, read chapter “An overview of Node.js: architecture, APIs, event loop, concurrency” in “Shell scripting with Node.js”. This blog post gives an overview of how Node.js works: What its architecture looks like. How its APIs are structured. A few highlights of its global variables and built-in modules. How it runs JavaScript in a single thread via an event
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テクノロジー
●2022/09/09 08:56
●Node.js
●あとで読む
2users
2ality.com
Warning: This blog post is outdated. Instead, read chapter “Parsing command line arguments with util.parseArgs()” in “Shell scripting with Node.js”. In this blog post, we explore how to use the Node.js function parseArgs() from module node:util to parse command line arguments. Imports that are implied in this blog post # The following two imports are implied in every example in this post: import
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テクノロジー
●2022/08/05 09:18
●Node.js
●article
3users
2ality.com
Warning: This blog post is outdated. Instead, read chapter “Running shell commands in child processes” in “Shell scripting with Node.js”. In this blog post, we’ll explore how we can execute shell commands from Node.js, via module 'node:child_process'. Overview of this blog post # Module 'node:child_process' has a function for executing shell commands (in spawned child processes) that comes in two
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テクノロジー
●2022/07/06 14:48
●Node.js
●article
4users
2ality.com
Ecma International approves ECMAScript 2022: What’s new? On 22 June 2022, the 123nd Ecma General Assembly approved the ECMAScript 2022 language specification, which means that it’s officially a standard now. This blog post explains what’s new. The editors of ECMAScript 2022 # The editors of this release are: Shu-yu Guo Michael Ficarra Kevin Gibbons What’s new in ECMAScript 2022? # New members of
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テクノロジー
●2022/06/23 10:47
●ECMAScript
●article
6users
2ality.com
Processing Arrays non-destructively: for-of vs. .reduce() vs. .flatMap() In this blog post, we look at three ways of processing Arrays: The for-of loop The Array method .reduce() The Array method .flatMap() The goal is to help you choose between these features whenever you need to process Arrays. In case you don’t know .reduce() and .flatMap() yet, they will both be explained to you. In order to g
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テクノロジー
●2022/05/27 09:09
●JavaScript
●article
3users
2ality.com
(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
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テクノロジー
●2022/05/19 09:09
●ECMAScript
●JavaScript
●web
4users
2ality.com
The triple dot syntax (...) in JavaScript: rest vs. spread In JavaScript, the same syntax – triple dots (...) – is used for two different mechanisms: Rest syntax is for receiving data. Spreading is for sending data. This blog post examines how these mechanisms work and why they are not operators. Receiving data: rest syntax # A rest parameter is a special kind of parameter that receives all remai
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テクノロジー
●2022/05/05 09:29
●JavaScript
3users
2ality.com
ECMAScript proposal “Change Array by copy”: four new non-destructive Array methods This blog post describes the ECMAScript proposal “Change Array by copy” by Robin Ricard and Ashley Claymore. It proposes four new methods for Arrays and Typed Arrays: .toReversed() .toSorted() .toSpliced() .with() The new methods are for Arrays and TypedArrays # This blog post only demonstrates the new methods with
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テクノロジー
●2022/04/12 08:24
●ECMAScript
●JavaScript
●article
2users
2ality.com
ECMAScript proposal: searching Arrays from end to start via .findLast() and .findLastIndex() This blog post describes the ECMAScript proposal “Array find from last” by Wenlu Wang and Daniel Rosenwasser. Topic of this blog post: methods of Arrays and of Typed Arrays # In this blog post, we explore methods of Arrays. But everything we learn also applies to Typed Arrays. Searching Arrays # The foll
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テクノロジー
●2022/03/26 10:36
3users
2ality.com
Update 2022-03-10: I’m quoting a few insightful tweets at the end of this blog post. The ECMAScript proposal “Types as comments” (by Gil Tayar, Daniel Rosenwasser, Romulo Cintra, Rob Palmer, and others) is about adding type annotations to JavaScript (there is also an accompanying blog post). Such type annotations would look similar to TypeScript’s and Flow’s annotations and are completely ignored
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テクノロジー
●2022/03/10 13:10
●JavaScript
●あとで読む
2users
2ality.com
Update 2022-03-10: I’m quoting a few insightful tweets at the end of this blog post. The ECMAScript proposal “Types as comments” (by Gil Tayar, Daniel Rosenwasser, Romulo Cintra, Rob Palmer, and others) is about adding type annotations to JavaScript (there is also an accompanying blog post). Such type annotations would look similar to TypeScript’s and Flow’s annotations and are completely ignored
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テクノロジー
●2022/03/10 11:53
2users
2ality.com
JavaScript naming conflicts: How existing code can force proposed features to be renamed Sometimes the name of a proposed feature (a method, a global variable, etc.) clashes with existing code and has to be changed. This blog post explains how that can happen and lists features that were renamed. Evolving JavaScript: Don’t break the web! # One core principle for evolving JavaScript is to not “bre
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テクノロジー
●2022/03/08 11:12
●JavaScript
3users
2ality.com
This blog post is first in a series of two: What are wrapper objects for primitive values? How do primitive values get their properties? Each of the primitive types boolean, number, bigint, string and symbol has an associated wrapper class (Boolean, Number, BigInt, String, Symbol). In this blog post, we examine what these classes are good for. Wrapper classes for primitive types # This is an exha
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テクノロジー
●2022/02/21 13:36
●javascript
●あとで読む
10users
2ality.com
The proposal “Pipe operator (|>) for JavaScript” (by J. S. Choi, James DiGioia, Ron Buckton and Tab Atkins) introduces a new operator. This operator is an idea borrowed from functional programming that makes applying functions more convenient in many cases. This blog post describes how the pipe operator works and what its use cases are (there are more than you might expect!). The two competing pro
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テクノロジー
●2022/01/27 21:02
●javascript
●proposal
2users
2ality.com
Spreading is a common technique for copying objects in JavaScript: Spreading into an Array literal to copy an Array Spreading into an Object literal to copy a plain object Spreading has one significant downside – it creates shallow copies: The top levels are copied, but property values are shared. structuredClone() is a new function that will soon be supported by most browsers, Node.js and Deno. I
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テクノロジー
●2022/01/17 14:35
●JavaScript
6users
2ality.com
Node.js now supports a node: protocol for built-in modules. The new node: protocol # Previously: import * as fs from 'fs/promises'; Now: import * as fs from 'node:fs/promises'; Benefits of node: imports # What are the benefits of using node: module specifiers? It’s immediately clear that a built-in Node.js module is imported. Given how many of them there now are, that’s useful information. There
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テクノロジー
●2021/12/13 14:37
●node.js
●article
●JavaScript
3users
2ality.com
The ECMAScript proposal “Class static initialization blocks” by Ron Buckton is at stage 4 and scheduled to be included in ECMAScript 2022. For setting up an instance of a class, we have two constructs in JavaScript: Field: Create (and optionally initialize) instance properties. Constructor: A block of code that is executed before setup is finished. For setting up the static part of a class, we onl
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テクノロジー
●2021/09/01 19:38
●ECMAScript
●javascript
13users
2ality.com
JavaScript needs more helper functions for iteration (map, filter, etc.) – where should we put them? Iteration is a standard that connects operations with data containers: Each operation that follows this standard, can be applied to each data container that implements this standard. In this blog post: We first explore three questions: How does JavaScript’s iteration work? What are its quirks? What
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テクノロジー
●2021/08/10 11:54
●JavaScript
●article
●あとで読む
5users
2ality.com
Simple monorepos via npm workspaces and TypeScript project references A monorepo is a single repository that is used to manage multiple projects. In this blog post, we’ll explore how to set up a simple monorepo for two npm packages. All we need is already built into npm and TypeScript. What is a monorepo and why is it useful? # Whenever we have to develop multiple interdependent npm packages in p
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テクノロジー
●2021/07/21 19:18
●monorepo
●TypeScript
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