keep-a-changelog/src/parser.js

Parse and generate changelogs following the [keepachangelog](https://keepachangelog.com/) format.

import Changelog from "./Changelog.js";
import Release from "./Release.js";
const defaultOptions = {
    releaseCreator: (version, date, description) => new Release(version, date, description),
    autoSortReleases: true,
};
/** Parse a markdown string */
export default function parser(markdown, options) {
    const opts = Object.assign({}, defaultOptions, options);
    const tokens = tokenize(markdown);
    try {
        return processTokens(tokens, opts);
    }
    catch (error) {
        throw new Error(`Parse error in the line ${tokens[0][0]}: ${error.message}`);
    }
}
/** Process an array of tokens to build the Changelog */
function processTokens(tokens, opts) {
    const changelog = new Changelog("");
    changelog.flag = getContent(tokens, "flag");
    changelog.title = getContent(tokens, "h1", true);
    changelog.description = getTextContent(tokens);
    changelog.autoSortReleases = opts.autoSortReleases;
    //Releases
    let release;
    while ((release = getContent(tokens, "h2").toLowerCase())) {
        const matches = release.match(/\[?([^\]]+)\]?\s*-\s*([\d]{4}-[\d]{1,2}-[\d]{1,2})(\s+\[yanked\])?$/);
        if (matches) {
            release = opts.releaseCreator(matches[1], matches[2]);
            release.yanked = !!matches[3];
        }
        else if (release.includes("unreleased")) {
            const matches = release.match(/\[?([^\]]+)\]?\s*-\s*unreleased(\s+\[yanked\])?$/);
            const yanked = release.includes("[yanked]");
            release = matches
                ? opts.releaseCreator(matches[1])
                : opts.releaseCreator();
            release.yanked = yanked;
        }
        else {
            throw new Error(`Syntax error in the release title`);
        }
        changelog.addRelease(release);
        release.description = getTextContent(tokens);
        let type;
        while ((type = getContent(tokens, "h3").toLowerCase())) {
            let change;
            while ((change = getContent(tokens, "li"))) {
                release.addChange(type, change);
            }
        }
    }
    //Skip release links
    let link = getContent(tokens, "link");
    while (link) {
        if (!changelog.url) {
            const matches = link.match(/^\[.*\]\:\s*(http.*?)\/(?:-\/)?(branches\/compare|branchCompare|compare)(\/|\?).*$/);
            if (matches) {
                changelog.url = matches[1];
            }
        }
        link = getContent(tokens, "link");
    }
    //Footer
    if (getContent(tokens, "hr")) {
        changelog.footer = getContent(tokens, "p");
    }
    if (tokens.length) {
        throw new Error(`Unexpected content ${JSON.stringify(tokens)}`);
    }
    return changelog;
}
/** Returns the content of a token */
function getContent(tokens, type, required = false) {
    const types = Array.isArray(type) ? type : [type];
    if (!tokens[0] || types.indexOf(tokens[0][1]) === -1) {
        if (required) {
            throw new Error(`Required token missing in: "${tokens[0][0]}"`);
        }
        return "";
    }
    return tokens.shift()[2].join("\n");
}
/** Return the next text content */
function getTextContent(tokens) {
    const lines = [];
    const types = ["p", "li"];
    while (tokens[0] && types.indexOf(tokens[0][1]) !== -1) {
        const token = tokens.shift();
        if (token[1] === "li") {
            lines.push("- " + token[2].join("\n"));
        }
        else {
            lines.push(token[2].join("\n"));
        }
    }
    return lines.join("\n");
}
/** Tokenize a markdown string */
function tokenize(markdown) {
    const tokens = [];
    markdown
        .trim()
        .split("\n")
        .map((line, index, allLines) => {
        const lineNumber = index + 1;
        if (line.startsWith("---")) {
            return [lineNumber, "hr", ["-"]];
        }
        if (line.startsWith("# ")) {
            return [lineNumber, "h1", [line.substr(1).trim()]];
        }
        if (line.startsWith("## ")) {
            return [lineNumber, "h2", [line.substr(2).trim()]];
        }
        if (line.startsWith("### ")) {
            return [lineNumber, "h3", [line.substr(3).trim()]];
        }
        if (line.startsWith("-")) {
            return [lineNumber, "li", [line.substr(1).trim()]];
        }
        if (line.startsWith("*")) {
            return [lineNumber, "li", [line.substr(1).trim()]];
        }
        if (line.match(/^\[.*\]\:\s*http.*$/)) {
            return [lineNumber, "link", [line.trim()]];
        }
        if (line.match(/^\[.*\]\:$/)) {
            const nextLine = allLines[index + 1];
            if (nextLine && nextLine.match(/\s+http.*$/)) {
                // We found a multi-line link: treat it like a single line
                allLines[index + 1] = "";
                return [lineNumber, "link", [
                        line.trim() + "\n" + nextLine.trimEnd(),
                    ]];
            }
        }
        const result = line.match(/^<!--(.*)-->$/);
        if (result) {
            return [lineNumber, "flag", [result[1].trim()]];
        }
        return [lineNumber, "p", [line.trimEnd()]];
    })
        .forEach((line, index) => {
        const [lineNumber, type, [content]] = line;
        if (index > 0) {
            const prevType = tokens[0][1];
            if (type === "p") {
                if (prevType === "p") {
                    return tokens[0][2].push(content);
                }
                if (prevType === "li") {
                    return tokens[0][2].push(content.replace(/^\s\s/, ""));
                }
            }
        }
        tokens.unshift([lineNumber, type, [content]]);
    });
    return tokens
        .filter((token) => !isEmpty(token[2]))
        .map((token) => {
        const content = token[2];
        while (isEmpty(content[content.length - 1])) {
            content.pop();
        }
        while (isEmpty(content[0])) {
            content.shift();
        }
        return token;
    })
        .reverse();
}
/** Check if a string or array is empty */
function isEmpty(val) {
    if (Array.isArray(val)) {
        val = val.join("");
    }
    return !val || val.trim() === "";
}