rudeshark.net/packages/client/src/scripts/check-word-mute.ts

export type Muted = {
	muted: boolean;
	matched: string[];
	what?: string;  // "note" || "reply" || "renote" || "quote"
};

const NotMuted = { muted: false, matched: [] };

function escapeRegExp(x: string) {
	return x.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"); // $& means the whole matched string
}

function checkWordMute(note: NoteLike): Muted {
	const text = ((note.cw ?? "") + " " + (note.text ?? "")).trim();
	if (text === "") return NotMuted;

	for (const mutePattern of mutedWords) {
		let mute: RegExp;
		let matched: string[];
		if (Array.isArray(mutePattern)) {
			matched = mutePattern.filter((keyword) => keyword !== "");
			if (matched.length === 0) {
				continue;
			}
			mute = new RegExp(
				`\\b${matched.map(escapeRegExp).join("\\b.*\\b")}\\b`,
				"g",
			);
		} else {
			const regexp = mutePattern.match(/^\/(.+)\/(.*)$/);
			// This should never happen due to input sanitisation.
			if (!regexp) {
				console.warn(`Found invalid regex in word mutes: ${mutePattern}`);
				continue;
			}
			mute = new RegExp(regexp[1], regexp[2]);
			matched = [mutePattern];
		}
		try {
			if (mute.test(text)) {
				return { muted: true, matched };
			}
		} catch (err) {
			// This should never happen due to input sanitisation.
		}
	}
}

export function getWordSoftMute(
	note: Record<string, any>,
	me: Record<string, any> | null | undefined,
	mutedWords: Array<string | string[]>,
): Muted {
	// 自分自身
	if (me && note.userId === me.id) {
		return NotMuted;
	}

	if (mutedWords.length > 0) {
		let noteMuted = checkWordMute(note);
		if (noteMuted.muted) {
			noteMuted.what = "note";
			return noteMuted;
		}

		if (note.reply) {
			let replyMuted = checkWordMute(note.reply);
			if (replyMuted.muted) {
				replyMuted.what = "reply";
				return replyMuted;
			}
		}

		if (note.renote) {
			let renoteMuted = checkWordMute(note.renote);
			if (renoteMuted.muted) {
				renoteMuted.what = (note.text == null ? "renote" : "quote");
				return renoteMuted;
			}
		}
	}

	return NotMuted;
}