@atomist/slack-messages/lib/Markdown.js

Atomist utilities for creating formatted Slack messages

"use strict";
/*
 * Copyright © 2021 Atomist, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.githubToSlack = exports.convertFormat = exports.convertLinks = exports.convertImageLinks = exports.convertInlineImages = exports.convertNamedLinks = void 0;
const splitProcessor_1 = require("./splitProcessor");
/**
 * Try to handle adjacent HTML and Markdown elements that cannot be
 * adjacent in Slack markup.  Used as the function argument of
 * replace.
 *
 * @param match the full match
 * @param url the URL
 * @param space trailing space, if it exists
 * @return properly padded replacement string
 */
function trailingSpace(match, url, space, offset, full) {
    const pad = offset + match.length === full.length ? "" : " ";
    return space ? url + space : url + pad;
}
/**
 * Replace named Markdown links with parenthesized links.
 *
 * @param text string which may have named Markdown links
 * @return string with explicit links
 */
function convertNamedLinks(text) {
    const namedLinksRegExp = /^\[(.+?)\]:\s*(https?:\/\/\S+).*\n/gm;
    let matches;
    const links = {};
    while ((matches = namedLinksRegExp.exec(text))) {
        // eslint-disable-line no-cond-assign
        const name = matches[1];
        const url = matches[2];
        links[name] = url;
    }
    let linked = text;
    for (const n of Object.keys(links)) {
        const u = links[n];
        const nameRegExp = new RegExp(`\\[(.+?)\\]\\[${n}\\]|\\[${n}\\]\\[\\]`, "g");
        linked = linked.replace(nameRegExp, (m, ln) => {
            const linkName = ln ? ln : n;
            return `[${linkName}](${u})`;
        });
    }
    return linked.replace(namedLinksRegExp, "");
}
exports.convertNamedLinks = convertNamedLinks;
/**
 * Replace <img> tags with just the image URL.
 *
 * @param text string which may have img tags
 * @return string with img tags replaced
 */
function convertInlineImages(text) {
    const regex = /(?:&lt;|<)img\s[\S\s]*?\bsrc="(\S+?)"[\S\s]*?(?:&gt;|>)(\s?)/g;
    return text.replace(regex, trailingSpace);
}
exports.convertInlineImages = convertInlineImages;
/**
 * Replace Markdown image links with just the image URL.
 *
 * @param text string with Markdown
 * @return string with image URLs
 */
function convertImageLinks(text) {
    return text.replace(/!\[.*?\]\((.+?)\)(\s?)/g, trailingSpace);
}
exports.convertImageLinks = convertImageLinks;
/**
 * Replace Markdown links with Slack markup links.
 *
 * @param text string with Markdown
 * @return string with Slack markup
 */
function convertLinks(text) {
    return text.replace(/\[([^\]]+?)\]\((.+?)\)/g, "<$2|$1>");
}
exports.convertLinks = convertLinks;
/**
 * Replace Markdown bold, italic, and unordered lists with their Slack
 * markup equivalent.
 *
 * @param text string with Markdown
 * @return string with Slack markup
 */
function convertFormat(text) {
    return text
        .replace(/^(\s*)[-*](\s+)/gm, "$1•$2")
        .replace(/(\*|_)\1(\S|\S.*?\S)\1\1(?!\1)/g, "<bdmkd>$2<bdmkd>")
        .replace(/(\*|_)(?!\1)(\S|\S.*?\S)\1(?!\1)/g, "<itmkd>$2<itmkd>")
        .replace(/<bdmkd>/g, "*")
        .replace(/<itmkd>/g, "_")
        .replace(/^([#]+)\s+([\S ]+)$/gm, `*$2*`);
}
exports.convertFormat = convertFormat;
/**
 * Convert sections of text from GitHub-flavored Markdown to Slack
 * message markup.  This function should not be passed inline code or
 * code blocks.  The ordering of the functions called is significant.
 *
 * @param text string containing Markdown
 * @return string converted to Slack markup
 */
function convertMarkdown(text) {
    const relinked = convertLinks(convertImageLinks(convertInlineImages(convertNamedLinks(text))));
    const urlSplitter = /(<.*>|https?:\/\/\S+)/g;
    return splitProcessor_1.splitProcessor(relinked, convertFormat, urlSplitter);
}
/** Provide a unique identifier for later replacement. */
function codeTag(i) {
    return `%.%CODE_PROCESSOR_CODE${i}%.%`;
}
/**
 * Transform everything but the interior of inline code segments,
 * i.e., \`code\`, but still be able to process elements that wrap
 * around inlide code formatting.
 *
 * @param text input string
 * @param transform function that takes the whole string with inline
 *                  code segments "hidden" and performs transformation
 * @return transformed string with unchanged inline code segments
 */
function codeProcessor(text) {
    const hunks = text.split(/(`.*?`)/);
    const codes = new Array(hunks.length);
    for (let i = 1; i < hunks.length; i += 2) {
        codes[i] = hunks[i];
        hunks[i] = codeTag(i);
    }
    const transformed = convertMarkdown(hunks.join(""));
    let restored = transformed;
    for (let i = 1; i < hunks.length; i += 2) {
        restored = restored.replace(codeTag(i), codes[i]);
    }
    return restored;
}
/**
 * Convert GitHub-flavored Markdown to Slack message markup.  This is
 * not a complete implementation of a Markdown parser, but it does its
 * level best.
 *
 * @param text string containing markdown
 * @return string with Slack markup
 */
function githubToSlack(text) {
    const codeBlock = /(```[\S\s]*?```(?!`))/g;
    return splitProcessor_1.splitProcessor(text, codeProcessor, codeBlock);
}
exports.githubToSlack = githubToSlack;
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