build.js

#!/usr/bin/env node

"use strict";

const fs = require("fs");
const browserify = require("browserify");
const config = require("./config");
const curDir = process.cwd();
const build_conf = config.build;

// Handle home page
const b = browserify();
b.add(`${curDir}/src/main.js`)
    .bundle()
    .pipe(fs.createWriteStream(`${curDir}/public/main.js`));

// Handle subpages
function getPageHtml(pageName, pageMeta) {
    let html = fs.readFileSync(`${curDir}/public/index.html`, "utf-8");
    const setMeta = function (metaName, value) {
        html = html.replace(
            html.match(new RegExp(`<meta\\s*name="${metaName}"[^>]+>`, "g")),
            `<meta name="${metaName}" content="${value}"/>`
        );
    };
    const setTitle = function () {
        html = html.replace(
            html.match(new RegExp(`<title.+</title>`, "g"))[0],
            `<title>${pageMeta.title}</title>`
        );
    };
    const setStyleSheet = function () {
        html = html.replace(
            html.match(new RegExp(`<link.+/style.css[^>]+>`, "g"))[0],
            `<link href="/style/style.css" rel="stylesheet" />`
        );
    };
    const setJs = function () {
        html = html.replace(
            html.match(new RegExp(`<script.+main.js.+</script>`, "g"))[0],
            `<script type="text/javascript" src="./${pageName}.js"></script>`
        );
    };
    const setAdditionalMeta = function (metas) {
        html = html.replace(
            "</head>",
            `${metas
                .map(kv => {
                    const [name, content] = kv;
                    return `<meta name="${name}" content="${content}"/>`;
                })
                .join("\n")}</head>`
        );
    };
    const setOgMeta = function () {
        const pageOgMeta = pageMeta.open_graph || {};

        const getOgMetaSearchRegex = function (name) {
            return new RegExp(`<meta\\s*property="og:${name}"[^>]+>`, "g");
        };
        const getDefaultOgMetaContent = function (name) {
            const getRegexMatch = function (source, searchRe) {
                const m = source.match(searchRe);
                return m ? m[0] : "";
            };
            return getRegexMatch(
                getRegexMatch(
                    getRegexMatch(html, getOgMetaSearchRegex(name)),
                    new RegExp(`content=".+"`, "g")
                ),
                new RegExp(`".+"`, "g")
            ).replace(/"/g, "");
        };
        const requiredOgMeta = [
            { key: "title", defaultValue: pageMeta.title },
            { key: "description", defaultValue: pageMeta.description },
            {
                key: "image",
                defaultValue: pageMeta.image || getDefaultOgMetaContent("image"),
            },
            {
                key: "url",
                defaultValue: (function () {
                    const urlContent = getDefaultOgMetaContent("url");

                    return `${urlContent}${
                        urlContent.charAt(urlContent.length - 1) !== "/" ? "/" : ""
                    }${pageName}`;
                })(),
            },
            {
                key: "locale",
                defaultValue: getDefaultOgMetaContent("locale"),
            },
            // TODO : handle locale:alternate meta tags array
        ];

        requiredOgMeta.forEach(entry => {
            const { key, defaultValue } = entry;
            html = html.replace(
                html.match(getOgMetaSearchRegex(key)),
                (function () {
                    const customValue = pageOgMeta[key];
                    if (!customValue)
                        return `<meta property="og:${key}" content="${defaultValue}"/>`;
                    else {
                        return Array.isArray(customValue)
                            ? customValue
                                  .map(alt => `<meta property="og:${key}" content="${alt}"/>`)
                                  .join("\n")
                            : `<meta property="og:${key}" content="${customValue}"/>`;
                    }
                })()
            );
        });
        const additionalOgMeta = Object.keys(pageMeta.open_graph).filter(
            k => !requiredOgMeta.map(rom => rom.key).includes(k)
        );

        if (additionalOgMeta.length > 0) {
            html = html.replace(
                "</head>",
                `${additionalOgMeta
                    .map(k => `<meta property="og:${k}" content="${pageMeta.open_graph[k]}"/>`)
                    .join("\n")}</head>`
            );
        }
    };
    setMeta("description", pageMeta.description);
    pageMeta.image && setMeta("image", pageMeta.image);
    setTitle();
    setStyleSheet();
    setJs();
    setAdditionalMeta(
        Object.entries(pageMeta).filter(kv => !build_conf.default_meta_keys.includes(kv[0]))
    );
    setOgMeta();
    return html;
}

const pages = fs.readdirSync(`${curDir}/src/pages`);

for (const p of pages) {
    const fPath = `${curDir}/src/pages/${p}`;
    const targetDirPath = `${curDir}/public/${p}`;

    if (!fs.existsSync(targetDirPath)) {
        fs.mkdirSync(targetDirPath);
    }

    const b = browserify();

    b.add(fPath)
        .bundle()
        .pipe(fs.createWriteStream(`${targetDirPath}/${p}.js`));

    const page = fs.createWriteStream(`${targetDirPath}/index.html`);
    const pageMeta = JSON.parse(fs.readFileSync(`${fPath}/meta.json`, "utf-8"));
    page.write(getPageHtml(p, pageMeta));
}

// If pages have been deleted in source, remove them in output directory too.
for (const dir of fs.readdirSync(`${curDir}/public`).filter(f => {
    if (build_conf.protected_dirs.includes(f)) return false;
    const stats = fs.statSync(`${curDir}/public/${f}`);
    return stats.isDirectory();
})) {
    if (!pages.includes(dir)) {
        const dPath = `${curDir}/public/${dir}`;
        try {
            const nestedFiles = fs.readdirSync(dPath);
            for (const nf of nestedFiles) {
                fs.unlinkSync(`${dPath}/${nf}`);
            }
            fs.rmdirSync(dPath);
        } catch (error) {
            console.error(error);
        }
    }
}