astro/dist/vite-plugin-html/transform/index.js

Astro is a modern site builder with web best practices, performance, and DX front-of-mind.

import MagicString from "magic-string";
import { collectSlots, SLOT_PREFIX } from "./slots.js";
import { escapeTemplateLiteralCharacters, needsEscape } from "./utils.js";
export async function transform(code, id) {
	const s = new MagicString(code, { filename: id });
	// Slots become real `${...}` expressions; everything else becomes static
	// template literal text and has its meaningful characters escaped.
	let cursor = 0;
	for (const slot of collectSlots(code)) {
		escapeRange(s, code, cursor, slot.start);
		s.overwrite(slot.start, slot.end, slot.value);
		cursor = slot.end;
	}
	escapeRange(s, code, cursor, code.length);
	s.prepend(`function render({ slots: ${SLOT_PREFIX} }) {\n\t\treturn \``);
	s.append("`\n	}\nrender[\"astro:html\"] = true;\nexport default render;");
	return {
		code: s.toString(),
		map: s.generateMap({ hires: "boundary" })
	};
}
function escapeRange(s, code, start, end) {
	if (start >= end) return;
	const segment = code.slice(start, end);
	if (needsEscape(segment)) {
		s.overwrite(start, end, escapeTemplateLiteralCharacters(segment));
	}
}