Convert Bluesky's datetime search to local time

bluesky-search-convert-local-time.ts

// https://github.com/golang/go/blob/519f6a00e4dabb871eadaefc8ac295c09fd9b56f/src/strings/strings.go#L377-L425
const fieldsfunc = (str: string, fn: (rune: number) => boolean): string[] => {
	const slices: string[] = [];

	let start = -1;
	for (let pos = 0, len = str.length; pos < len; pos++) {
		if (fn(str.charCodeAt(pos))) {
			if (start !== -1) {
				slices.push(str.slice(start, pos));
				start = -1;
			}
		} else {
			if (start === -1) {
				start = pos;
			}
		}
	}

	if (start !== -1) {
		slices.push(str.slice(start));
	}

	return slices;
};

const str = '"from:me hello world" from:me hello world since:2024-04-13 until:2024-04-14';

const DATE_RE = /^(\d{4})-(\d{2})-(\d{2})$/;

// https://github.com/bluesky-social/indigo/blob/421e4da5307f4fcba51f25b5c5982c8b9841f7f6/search/parse_query.go#L15-L21
let quoted = false;
const parts = fieldsfunc(str, (rune) => {
	if (rune === 34) {
		quoted = !quoted;
	}

	return rune === 32 && !quoted;
});

for (let i = 0, il = parts.length; i < il; i++) {
	const part = parts[i];

	if (part.charCodeAt(0) === 34) {
		continue;
	}

	const colon_index = part.indexOf(':');
	if (colon_index === -1) {
		continue;
	}

	const operator = part.slice(0, colon_index);
	const value = part.slice(colon_index + 1);

	if (operator === 'since' || operator === 'until') {
		const match = DATE_RE.exec(value);
		if (match === null) {
			continue;
		}

		const s = operator === 'since';

		const [, year, month, day] = match;
		const date = new Date(+year, +month - 1, +day, s ? 0 : 23, s ? 0 : 59, s ? 0 : 59, s ? 0 : 999);

		if (Number.isNaN(date.getTime())) {
			continue;
		}

		parts[i] = `${operator}:${date.toISOString()}`;
	}
}

console.log(parts.join(' '));