function substratum({
debug = false,
invalidation,
messageWhenInactive = md`⏸️ _Substratum styles are not loaded._`,
messageWhenActive = md`✅ _Substratum styles are loaded._`
} = {}) {
if (invalidation == null) {
throw new Error(
"invalidation is not provided. See: https://github.com/observablehq/stdlib/#invalidation"
);
}
if (!isRunningStandalone && !debug) return messageWhenInactive;
installStyles({ invalidation });
return messageWhenActive;
}
function installStyles({ invalidation }) {
let elements = new Set();
function detach(elements) {
for (let n of elements) {
n.remove();
elements.delete(n);
}
}
function attach(nodes) {
for (let n of nodes) {
document.head.prepend(n);
elements.add(n);
}
}
invalidation.then(() => detach(elements));
detach(elements);
const newStyleElements = new Set(
[html`<style>${reset}`, html`<style>${main}`].reverse()
);
attach(newStyleElements);
}
substratum({ debug, invalidation })
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