feat(jsx): add fetchpriority attribute to img, link, script, and iframe - #6803
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johnjenkins merged 1 commit intoAug 3, 2026
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Add the standardized `fetchPriority`/`fetchpriority` attribute (values: 'high' | 'low' | 'auto') to the JSXBase interfaces for IframeHTMLAttributes, ImgHTMLAttributes, LinkHTMLAttributes, and ScriptHTMLAttributes. The `fetchpriority` attribute is now a W3C standard that supersedes the older non-standard `importance` hint. Both camelCase and lowercase variants are added to match Stencil's existing dual-property convention. fixes: stenciljs#6802
johnjenkins
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Aug 3, 2026
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What is the current behavior?
The JSX type declarations in
stencil-public-runtime.tsdo not include the standardizedfetchpriorityattribute for<img>,<link>,<script>, or<iframe>elements. Using it in a Stencil JSX template produces a TypeScript error.GitHub Issue Number: #6802
What is the new behavior?
Adds
fetchPriority?: 'high' | 'low' | 'auto'andfetchpriority?: 'high' | 'low' | 'auto'to the followingJSXBaseinterfaces:IframeHTMLAttributesImgHTMLAttributesLinkHTMLAttributesScriptHTMLAttributesBoth camelCase and lowercase variants are added to match Stencil's existing dual-property convention (e.g.
crossOrigin/crossorigin,srcSet/srcset).Documentation
No documentation changes required — this is a type declaration update only.
Does this introduce a breaking change?
Testing
The change is a pure type-declaration addition with no runtime behavior. Verified by:
fetchpriority="high"/fetchPriority="high"on the affected elements after the change.Other information
fetchpriorityis now broadly supported across Chrome, Edge, Firefox, and Safari.importanceattribute already present in these interfaces is intentionally left unchanged for backward compatibility.