--- title: "Soon We Can Finally Banish JavaScript to the ShadowRealm" url: https://daily.dev/posts/soon-we-can-finally-banish-javascript-to-the-shadowrealm-blqbecewd source_url: https://css-tricks.com/soon-we-can-finally-banish-javascript-to-the-shadowrealm type: article source: "CSS-Tricks" published: 2026-05-12T13:59:46.434Z updated: 2026-05-12T14:00:25.815Z tags: ["webdev", "javascript"] reading_time: 11 upvotes: 2 comments: 0 language: 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. # Soon We Can Finally Banish JavaScript to the ShadowRealm **[CSS-Tricks](https://daily.dev/sources/css_tricks)** · 11 min read · 2 upvotes · 0 comments ## Summary The TC39 ShadowRealm proposal (currently at Stage 2.7) introduces a new kind of JavaScript realm designed purely for isolation. Unlike iframes or Web Workers, a ShadowRealm has its own global and built-in objects but shares the host realm's execution thread, avoiding multi-threading complexity. Code evaluated inside a ShadowRealm cannot interfere with the outer realm's global scope, making it useful for clean-room testing, sandboxing third-party libraries, and preventing global scope pollution. The API exposes just two methods: `evaluate` for running string expressions and `importValue` for dynamically importing ES modules into the ShadowRealm. It is not yet in browsers or the ES-262 standard. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: --- Tags: [#webdev](https://daily.dev/tags/webdev), [#javascript](https://daily.dev/tags/javascript) [View this post on daily.dev](https://daily.dev/posts/soon-we-can-finally-banish-javascript-to-the-shadowrealm-blqbecewd)