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Simplify font preloading #499

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Merged
merged 2 commits into from
Mar 5, 2025
Merged

Simplify font preloading #499

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4c15237
Simplify font preloading
jonatanklosko Mar 5, 2025
1008855
Add timeout
jonatanklosko Mar 5, 2025
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69 changes: 22 additions & 47 deletions assets/packs/data_table/main.js
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Original file line number Diff line number Diff line change
Expand Up @@ -9,61 +9,36 @@ import { createTableSkeleton } from "./Skeleton";
export async function init(ctx, data) {
ctx.root.appendChild(createTableSkeleton());

try {
await loadStyles(ctx);
} finally {
const root = createRoot(ctx.root);
root.render(<App ctx={ctx} data={data} />);
}
}

async function loadStyles(ctx) {
const cssPromises = [
await Promise.all([
ctx.importCSS(
"https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;600&display=swap",
),
ctx.importCSS(
"https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap",
),
ctx.importCSS("main.css"),
];
]);

// We force all fonts to be loaded by adding an invisible element,
// and then we explicitly wait for the fonts to finish loading.
// We force all fonts to be loaded before rendering the table.
// This is important on first uncached render. If we don't wait
// and render the table with fallback fonts, the columns get wrong
// default widths. Also, on Firefox ans Safari, once the font is
// loaded, the table only updates on hover, which is bad UX.

const fontPreloader = document.createElement("div");
fontPreloader.setAttribute("aria-hidden", "true");
fontPreloader.style.cssText = `
position: absolute;
visibility: hidden;
left: -9999px;
`;
fontPreloader.innerHTML = `
<span style="font-family: 'JetBrains Mono'">
<span style="font-weight: 400">preload</span>"
<span style="font-weight: 500">preload</span>"
<span style="font-weight: 600">preload</span>"
</span>"
<span style="font-family: 'Inter'">
<span style="font-weight: 400">preload</span>"
<span style="font-weight: 500">preload</span>"
<span style="font-weight: 600">preload</span>"
</span>"
`;

document.body.appendChild(fontPreloader);

try {
await Promise.all(cssPromises);

if (document.fonts && document.fonts.ready) {
await document.fonts.ready;
}
} finally {
document.body.removeChild(fontPreloader);
}
// default widths. Also, in Firefox ans Safari, once the font is
// loaded, the table only updates on hover, which is bad UX. That
// said, in Firefox, this doesn't help 100% of the time either.
await Promise.race([
Promise.all([
document.fonts.load("400 16px 'JetBrains Mono'"),
document.fonts.load("500 16px 'JetBrains Mono'"),
document.fonts.load("600 16px 'JetBrains Mono'"),
document.fonts.load("400 16px Inter"),
document.fonts.load("500 16px Inter"),
document.fonts.load("600 16px Inter"),
]),
// If a font request fails, the promises may not be resolved, so
// we add a timeout just to make sure this finishes at some point.
new Promise((resolve) => setTimeout(resolve, 5000)),
]);

const root = createRoot(ctx.root);
root.render(<App ctx={ctx} data={data} />);
}
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