forgor lol

utils/blog.ts

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+/**
+ * Copyright (c) 2025 miwa
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+export interface ReadingTimeOptions {
+	wordsPerMinute?: number;
+	imageTime?: number;
+	codeBlockTime?: number;
+	chineseKoreanReadingSpeed?: number;
+}
+
+export interface ReadingTimeResult {
+	minutes: number;
+	words: number;
+	images: number;
+	codeBlocks: number;
+}
+
+export function formatReadingTime(input: ReadingTimeResult) {
+	return `${input.words} words · ${
+		input.images ? `${input.images} images · ` : ""
+	}${
+		input.codeBlocks ? `${input.codeBlocks} code blocks · ` : ""
+	}${input.minutes} minutes`;
+}
+
+export function calculateReadingTime(
+	input: string,
+	options: ReadingTimeOptions = {},
+): ReadingTimeResult {
+	const {
+		wordsPerMinute = 200,
+		imageTime = 12,
+		codeBlockTime = 15,
+		chineseKoreanReadingSpeed = 260,
+	} = options;
+
+	let images = 0, preBlocks = 0, codeBlocks = 0;
+
+	const text = input
+		.replace(/<img[^>]*>/gi, () => (images++, ""))
+		.replace(/<pre[^>]*>[\s\S]*?<\/pre>/gi, () => (preBlocks++, ""))
+		.replace(/<code[^>]*>[\s\S]*?<\/code>/gi, () => (codeBlocks++, ""));
+
+	const cjkRegex = /[\u4E00-\u9FFF\u3040-\u309F\u30A0-\u30FF\uAC00-\uD7AF]/g;
+	const cjkMatches = text.match(cjkRegex);
+	const cjkCharacters = cjkMatches?.length ?? 0;
+
+	const textWithoutCJK = cjkCharacters ? text.replace(cjkRegex, " ") : text;
+	const words = textWithoutCJK.trim().split(/\s+/).reduce(
+		(n, w) => n + (w && /\w/.test(w) ? 1 : 0),
+		0,
+	);
+
+	const totalMinutes = Math.ceil(
+		words / wordsPerMinute +
+			cjkCharacters / chineseKoreanReadingSpeed +
+			(images * imageTime + (preBlocks + codeBlocks) * codeBlockTime) / 60,
+	);
+
+	return {
+		minutes: Math.max(totalMinutes || 2, 2),
+		words: words + cjkCharacters,
+		images,
+		codeBlocks: preBlocks + codeBlocks,
+	};
+}