PERF003 · Preload missing as
Severity: warning
What it checks
Section titled “What it checks”Every <link rel="preload"> must have an as attribute naming the resource type (style, script, font, image, …). A preload without as is flagged.
Why it matters
Section titled “Why it matters”A <link rel="preload"> without an as attribute is ignored by the browser (or fetched a second time), wasting the preload.
How to fix
Section titled “How to fix”Add an as attribute matching the resource type:
<link rel="preload" href="/app.css" as="style" />