--- title: What's new in ECMAScript 2026 | daily.dev description: ECMAScript 2026 was officially approved by Ecma International on 30 June 2026. The new additions include: Array.fromAsync for converting async iterators to... canonical: https://daily.dev/posts/zwgowrsd6 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: What's new in ECMAScript 2026 | daily.dev og:description: ECMAScript 2026 was officially approved by Ecma International on 30 June 2026. The new additions include: Array.fromAsync for converting async iterators to... og:url: https://daily.dev/posts/zwgowrsd6 og:image: https://api.daily.dev/og/posts/zwgowrSd6.png og:image:alt: Post cover image og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # What's new in ECMAScript 2026 **[Alexey Zerkalenkov](https://daily.dev/sources/tzhsbevyajhcmr0fmoxfj)** · [@alexeyzerkalenkov](https://daily.dev/alexeyzerkalenkov) · 154 upvotes · 9 comments ## Summary ECMAScript 2026 was officially approved by Ecma International on 30 June 2026. The new additions include: Array.fromAsync for converting async iterators to arrays, Error.isError as a safer alternative to instanceof Error, Math.sumPrecise for accurate floating-point summation, built-in Uint8Array to/from Base64 and hex conversion, Iterator.concat for sequencing iterators, JSON.parse source text access to handle BigInt precision issues, and Map/WeakMap getOrInsert (Upsert) to eliminate boilerplate key-existence checks. Each feature is explained with concise before/after code examples. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community discussion Top comments from developers on daily.dev. **@logan31820** · 12 upvotes > One of the most insightful blog of the day, great work pal. > Thanks for sharing **@jenueldev** · 7 upvotes > Great ECMAScript roundup. **@kunalpan24** · 4 upvotes > Liked the addition of `getOrInsert` in map. Great update! **@devmount** · 1 upvotes > Would be even better to have `getOrInsert` for arrays too! ## Similar posts on daily.dev - [Don’t just attend KubeCon \+ CloudNativeCon, Merge Forward your experience\!](https://daily.dev/posts/don-t-just-attend-kubecon-cloudnativecon-merge-forward-your-experience--l0rpp73x8) · CNCF · 1 upvotes · 0 comments - [Announcing H2 2026 KCDs](https://daily.dev/posts/announcing-h2-2026-kcds-m96goajm1) · CNCF · 1 upvotes · 0 comments - [Two months of Open Community Groups](https://daily.dev/posts/two-months-of-open-community-groups-asf52zhbs) · CNCF · 0 upvotes · 0 comments --- Tags: [#webdev](https://daily.dev/tags/webdev), [#javascript](https://daily.dev/tags/javascript) [View this post on daily.dev](https://daily.dev/posts/zwgowrsd6) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/zwgowrsd6","headline":"What's new in ECMAScript 2026","text":"Shared: What's new in ECMAScript 2026","url":"https://daily.dev/posts/zwgowrsd6","datePublished":"2026-07-09T05:27:02.687Z","dateModified":"2026-07-10T06:17:41.408Z","author":{"@type":"Person","name":"Alexey Zerkalenkov","url":"https://daily.dev/alexeyzerkalenkov","image":"https://lh3.googleusercontent.com/a/ACg8ocKQBwPwaHC4XrPy0rniDybogCxlwDp7QCLkbwsqNRQSFhqDIlIf=s96-c","description":"Fullstack AI Engineer","interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"EndorseAction"},"userInteractionCount":8470}},"image":"https://media.daily.dev/image/upload/s--HRgLpUt6--/f_auto/v1722860399/public/Placeholder%2003","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":154},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":9}],"sharedContent":{"@type":"WebPage","url":"https://api.daily.dev/r/M7U4aplgI"},"comment":[{"@type":"Comment","text":"One of the most insightful blog of the day, great work pal.\nThanks for sharing","datePublished":"2026-07-09T16:42:10.160Z","url":"https://daily.dev/posts/zwgowrSd6#c-gL2w5Aax9","author":{"@type":"Person","name":"Shaikh Mohd Noman","url":"https://daily.dev/logan31820","image":"https://lh3.googleusercontent.com/a-/AOh14Gg0Plm3eMtv5jY_hUcjKPUzOs8Wy3KjqS-P8Ljk1Q=s100"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":12}},{"@type":"Comment","text":"Great ECMAScript roundup.","datePublished":"2026-07-09T23:05:28.460Z","url":"https://daily.dev/posts/zwgowrSd6#c-vv3zBRMNE","author":{"@type":"Person","name":"Jenuel Oras Ganawed","url":"https://daily.dev/jenueldev","image":"https://media.daily.dev/image/upload/s--BadmiNyj--/f_auto/v1787625077/avatars/avatar_JJtZr4Sjm?_a=BAMAMicg0"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":7}},{"@type":"Comment","text":"Liked the addition of getOrInsert in map. Great update!","datePublished":"2026-07-10T10:46:23.387Z","url":"https://daily.dev/posts/zwgowrSd6#c-bSBtxqX6P","author":{"@type":"Person","name":"Kunal Panchal","url":"https://daily.dev/kunalpan24","image":"https://media.daily.dev/image/upload/s--O0TOmw4y--/f_auto/v1715772965/public/noProfile"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":4}},{"@type":"Comment","text":"Would be even better to have getOrInsert for arrays too!","datePublished":"2026-07-10T15:22:11.886Z","url":"https://daily.dev/posts/zwgowrSd6#c-hFcYGZzrc","author":{"@type":"Person","name":"Andreas","url":"https://daily.dev/devmount","image":"https://media.daily.dev/image/upload/s--0yHQgkD3--/f_auto/v1730121566/avatars/avatar_wkPuMtV83z5WseTrVc5QU"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1}}],"isPartOf":{"@type":"WebPage","url":"https://daily.dev/sources/tzhsbevyajhcmr0fmoxfj","name":"Alexey Zerkalenkov"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Alexey Zerkalenkov","item":"https://daily.dev/sources/tzhsbevyajhcmr0fmoxfj"},{"@type":"ListItem","position":3,"name":"What's new in ECMAScript 2026"}]} ```