subsrt-ts/dist/format/lrc.js

Subtitle JavaScript library and command line tool with no dependencies.

import { buildHandler } from "../handler.js";
const FORMAT_NAME = "lrc";
const helper = {
    /**
     * Converts a time string in format of mm:ss.ff or mm:ss,ff to milliseconds.
     * @param s The time string to convert
     * @throws {TypeError} If the time string is invalid
     * @returns Milliseconds
     */
    toMilliseconds: (s) => {
        const match = /^\s*(\d+):(\d{1,2})(?:[.,](\d{1,3}))?\s*$/.exec(s);
        if (!match) {
            throw new TypeError(`Invalid time format: ${s}`);
        }
        const mm = parseInt(match[1], 10);
        const ss = parseInt(match[2], 10);
        const ff = match[3] ? parseInt(match[3], 10) : 0;
        const ms = mm * 60 * 1000 + ss * 1000 + ff * 10;
        return ms;
    },
    /**
     * Converts milliseconds to a time string in format of mm:ss.ff.
     * @param ms Milliseconds
     * @returns Time string in format of mm:ss.ff
     */
    toTimeString: (ms) => {
        const mm = Math.floor(ms / 1000 / 60);
        const ss = Math.floor((ms / 1000) % 60);
        const ff = Math.floor(ms % 1000);
        const time = `${(mm < 10 ? "0" : "") + mm}:${ss < 10 ? "0" : ""}${ss}.${ff < 100 ? "0" : ""}${ff < 10 ? "0" : Math.floor(ff / 10)}`;
        return time;
    },
};
/**
 * Parses captions in LRC format.
 * @param content The subtitle content
 * @param options Parse options
 * @returns Parsed captions
 * @see https://en.wikipedia.org/wiki/LRC_%28file_format%29
 */
const parse = (content, options) => {
    let prev = null;
    const captions = [];
    // const eol = options.eol || "\r\n";
    const parts = content.split(/\r?\n/);
    for (const part of parts) {
        if (!part || part.trim().length === 0) {
            continue;
        }
        // LRC content
        const regex = /^\[(\d{1,2}:\d{1,2}(?:[.,]\d{1,3})?)\](.*)(?:\r?\n)*$/;
        const match = regex.exec(part);
        if (match) {
            const caption = {};
            caption.type = "caption";
            caption.start = helper.toMilliseconds(match[1]);
            caption.end = caption.start + 2000;
            caption.duration = caption.end - caption.start;
            caption.content = match[2];
            caption.text = caption.content;
            captions.push(caption);
            // Update previous
            if (prev) {
                prev.end = caption.start;
                prev.duration = prev.end - prev.start;
            }
            prev = caption;
            continue;
        }
        // LRC meta
        const meta = /^\[(\w+):([^\]]*)\](?:\r?\n)*$/.exec(part);
        if (meta) {
            const caption = {};
            caption.type = "meta";
            caption.tag = meta[1];
            if (meta[2]) {
                caption.data = meta[2];
            }
            captions.push(caption);
            continue;
        }
        if (options.verbose) {
            console.warn("Unknown part", part);
        }
    }
    return captions;
};
/**
 * Builds captions in LRC format.
 * @param captions The captions to build
 * @param options Build options
 * @returns The built captions string in LRC format
 * @see https://en.wikipedia.org/wiki/LRC_%28file_format%29
 */
const build = (captions, options) => {
    var _a;
    let content = "";
    let lyrics = false;
    const eol = (_a = options.eol) !== null && _a !== void 0 ? _a : "\r\n";
    for (const caption of captions) {
        if (caption.type === "meta") {
            if (caption.tag && caption.data && typeof caption.data === "string") {
                content += `[${caption.tag}:${caption.data.replace(/[\r\n]+/g, " ")}]${eol}`;
            }
            continue;
        }
        if (!caption.type || caption.type === "caption") {
            if (!lyrics) {
                content += eol; //New line when lyrics start
                lyrics = true;
            }
            content += `[${helper.toTimeString(caption.start)}]${caption.text}${eol}`;
            continue;
        }
        if (options.verbose) {
            console.log("SKIP:", caption);
        }
    }
    return content;
};
/**
 * Detects whether the content is in LRC format.
 * @param content The subtitle content
 * @returns Format name if detected, or null if not detected
 */
const detect = (content) => {
    /*
    [04:48.28]Sister, perfume?
    */
    return /\r?\n\[\d+:\d{1,2}(?:[.,]\d{1,3})?\].*\r?\n/.test(content);
};
export default buildHandler({ name: FORMAT_NAME, build, detect, helper, parse });
export { FORMAT_NAME as name, build, detect, helper, parse };