Needs as attribute

[kurtextrem]

See here: https://www.smashingmagazine.com/2016/02/preload-what-is-it-good-for/#loading-of-late-discovered-resources
If the as attribute is omitted from the preload, it has lower priority or isn't even used at all (Chrome shows: was preloaded using link preload but not used within a few seconds from the window's load event. Please make sure it wasn't preloaded for nothing.

[beheh]

This seems to work for me locally. The plugin is choosing the attribute based on the extension:

resource-hints-webpack-plugin/index.js

Lines 7 to 17 in bbac509

	var preloadDirective = {
	'.js': 'script',
	'.css': 'style',
	'.woff': 'font',
	'.woff2': 'font',
	'.jpeg': 'image',
	'.jpg': 'image',
	'.gif': 'image',
	'.png': 'image',
	'.svg': 'image'
	};

And it's correctly set in the fixture (only for preload though - prefetch doesn't have an as attribute).

resource-hints-webpack-plugin/spec/fixtures/expected.html

Line 6 in bbac509

<link rel="preload" href="bundle.js" as="script"><link rel="prefetch" href="bundle.js"></head>