Function adoptionAgency

lib/html/syntax.js:5376–5496

(
		/** @type {string} */ subject,
		/** @type {TagPos | null} */ pos
	)

	// ---------- adoption agency algorithm ----------
	const adoptionAgency = (
		/** @type {string} */ subject,
		/** @type {TagPos | null} */ pos
	) => {
		// step 1
		const c = cur();
		if (
			c.namespace === NS_HTML &&
			c.tagName === subject &&
			!afe.some((e) => !e.marker && e.element === c)
		) {
			open.pop();
			return true;
		}
		let outer = 0;
		while (outer < 8) {
			outer++;
			// find formatting element
			let fmtIdx = -1;
			for (let i = afe.length - 1; i >= 0; i--) {
				if (afe[i].marker) break;
				if (
					afeEl(afe[i]).tagName === subject &&
					afeEl(afe[i]).namespace === NS_HTML
				) {
					fmtIdx = i;
					break;
				}
			}
			if (fmtIdx === -1) return false; // act as any other end tag
			const fmt = afeEl(afe[fmtIdx]);
			const openIdx = open.indexOf(fmt);
			if (openIdx === -1) {
				afe.splice(fmtIdx, 1);
				return true;
			}
			if (!inScopeEl(fmt)) return true; // parse error, ignore
			// step: furthest block
			let furthestIdx = -1;
			for (let i = openIdx + 1; i < open.length; i++) {
				if (isSpecial(open[i])) {
					furthestIdx = i;
					break;
				}
			}
			if (furthestIdx === -1) {
				while (open.length > openIdx) open.pop();
				afe.splice(fmtIdx, 1);
				return true;
			}
			const furthest = open[furthestIdx];
			const commonAncestor = open[openIdx - 1];
			let bookmark = fmtIdx;
			let node = furthest;
			let lastNode = furthest;
			let nodeIdx = furthestIdx;
			let inner = 0;
			while (true) {