ipx/web/build.mjs

// Builds the frontend (#203): each page's TypeScript from web/src, types stripped and minified
// by swc into a script of its own (app.js, login.js), the page minified, its <script data-src>
// pointing at that script, and the icons, logos and typeface beside them. The result, web/dist,
// is a static site: Caddy serves it (web/Caddyfile, Dockerfile.web) and passes the API to ipx.
//
// The page names its script with a hash of the script's contents, /app.js?v=<hash>, and the
// server lets a browser keep that for a year without asking again. A changed script is a new
// URL, and the page, which the browser checks on every visit, is what carries it. Caddy's file
// server ignores the query.
//
//   node web/build.mjs [out-dir]      default out-dir: web/dist
import crypto from 'node:crypto';
import fs from 'node:fs';
import path from 'node:path';
import zlib from 'node:zlib';
import { fileURLToPath } from 'node:url';
import { createRequire } from 'node:module';
import swc from '@swc/core';
import html from '@swc/html';

const here = path.dirname(fileURLToPath(import.meta.url));
// A build for measuring what the browser tests run (#390), IPX_COVERAGE=1: the script not minified
// and with a source map back to each file of web/src, which concat-map.mts makes. Loaded only then:
// it is TypeScript, which the Node of Dockerfile.web does not run.
// Required, not imported with a top-level await, which would stop the tests require()ing this file.
const coverageMap = process.env.IPX_COVERAGE ? createRequire(import.meta.url)('./concat-map.mts').concatMap : null;
// The page's own version (package.json), given to its script in place of __WEB_VERSION__.
const WEB_VERSION = JSON.parse(fs.readFileSync(path.join(here, '..', 'package.json'), 'utf8')).version;

// The files are one script, concatenated in this order, not modules: they share one top-level
// scope, as the single inline script did, and code that runs at load needs what came before it.
const PAGES = {
  'index.html': { script: 'app.js', src: ['util', 'theme', 'feeds', 'feedpage', 'items', 'player', 'dialogs', 'signals', 'gestures', 'offline', 'events', 'native'] },
  'admin.html': { script: 'admin.js', src: ['util', 'theme', 'admin'] },
  'login.html': { script: 'login.js', src: ['login'] },
};
// The stylesheet the app and admin pages share, served and named by hash as the scripts are.
const STYLE = 'app.css';

const hash = s => crypto.createHash('sha256').update(s).digest('hex').slice(0, 12);

// hls.js, for browsers that cannot play DeadAir's playlists themselves (#181). Served as it comes,
// by a name with its hash in it, which the page's script is given in place of __HLS_JS__.
const HLS = fs.readFileSync(path.join(here, '..', 'node_modules', 'hls.js', 'dist', 'hls.light.min.js'), 'utf8');
const HLS_URL = `/hls.js?v=${hash(HLS)}`;

// Font Awesome Free, the set the page's own icons come from, whole, for a Signal's icon (#261):
// each icon a file of its own, /icons/<style>/<name>.svg, drawn as a mask so it takes the theme's
// colour, and an index of names and search terms the picker fetches when it opens. The page's
// script is given the index's address, named by its hash, in place of __ICONS__.
const FA = path.join(here, '..', 'node_modules', '@fortawesome', 'fontawesome-free');
const FA_STYLES = ['solid', 'regular', 'brands'];
/// [`style/name`, label, search terms] for every icon, solid first.
export function iconIndex() {
  const meta = JSON.parse(fs.readFileSync(path.join(FA, 'metadata', 'icon-families.json'), 'utf8'));
  return FA_STYLES.flatMap(style => fs.readdirSync(path.join(FA, 'svgs', style)).sort().map(f => {
    const name = f.slice(0, -4), m = meta[name] || {};
    return [`${style}/${name}`, m.label || name, (m.search?.terms || []).join(' ')];
  }));
}
const ICONS = JSON.stringify(iconIndex());
const ICONS_URL = `/icons/index.json?v=${hash(ICONS)}`;

/// The shared stylesheet, minified. @swc/html minifies CSS inside a page, so it goes through as
/// one; the doctype only keeps it from complaining that a fragment has none.
export function buildStyle({ minify = true } = {}) {
  const css = fs.readFileSync(path.join(here, STYLE), 'utf8');
  if (!minify) return css;
  const r = html.minifySync(`<!doctype html><style>${css}</style>`, { minifyCss: true, removeComments: true });
  const bad = (r.errors || []).filter(e => e.level === 'error' || e.level === 'Error');
  if (bad.length) throw new Error(`${STYLE}: ${bad.map(e => e.message).join('; ')}`);
  const out = r.code.slice(r.code.indexOf('<style>') + 7, r.code.lastIndexOf('</style>'));
  // The minifier drops the space between a calc() and the value after it in a shorthand --
  // `padding:7px calc(12px + var(--safe-r))7px ...` -- and a browser throws the whole
  // declaration away, so the element silently loses its padding. It reports no error and the
  // page still loads, which is why this is checked rather than trusted. Longhands avoid it.
  const run = out.match(/calc\([^()]*(?:\([^()]*\)[^()]*)*\)(?=[0-9a-zA-Z.])/);
  if (run) throw new Error(`${STYLE}: minifying ran ${run[0]} into the value after it; use longhand properties`);
  return out;
}

/// The offline service worker (#389), web/sw/sw.ts made JavaScript, at the top of the site.
export function buildWorker({ minify = true } = {}) {
  const src = fs.readFileSync(path.join(here, 'sw', 'sw.ts'), 'utf8');
  return swc.transformSync(src, {
    filename: 'sw.ts',
    jsc: { parser: { syntax: 'typescript' }, target: 'es2022', minify: minify ? { compress: true, mangle: true } : undefined },
    isModule: false,
    minify,
  }).code;
}

/// The page and its script, built: { html, js, script }, where script is the file's name.
export function buildPage(name, { minify = !coverageMap } = {}) {
  const { script, src: files } = PAGES[name];
  const parts = files.map(f => ({ name: `web/src/${f}.ts`, text: fs.readFileSync(path.join(here, 'src', f + '.ts'), 'utf8') }));
  const src = parts.map(p => p.text).join('\n')
    .replaceAll('__HLS_JS__', HLS_URL)
    .replaceAll('__ICONS__', ICONS_URL)
    .replaceAll('__WEB_VERSION__', WEB_VERSION);
  const js = swc.transformSync(src, {
    filename: name + '.ts',
    jsc: {
      parser: { syntax: 'typescript' },
      target: 'es2022',
      // Top-level names stay as they are: markup calls some of them by name (onclick="closeModal()")
      // and the browser tests reach others (player, savePos) through page.evaluate.
      minify: minify ? { compress: { toplevel: false }, mangle: { toplevel: false } } : undefined,
    },
    isModule: false,
    minify,
    ...(coverageMap ? { sourceMaps: 'inline', inputSourceMap: JSON.stringify(coverageMap(parts)) } : {}),
  }).code;
  const page = fs.readFileSync(path.join(here, name), 'utf8');
  const marker = /<script data-src="[^"]*"><\/script>/;
  if (!marker.test(page)) throw new Error(`${name} has no <script data-src> to put its script in`);
  // Where the inline script was, and a plain <script src>, so it still runs in the same place:
  // after the markup it wires up, before anything else.
  let out = page.replace(marker, `<script src="/${script}?v=${hash(js)}"></script>`);
  out = out.replace(/<link rel="stylesheet" data-src="[^"]*">/,
    () => `<link rel="stylesheet" href="/${STYLE}?v=${hash(buildStyle({ minify }))}">`);
  // The icons are named by their contents too. They are kept a day under a fixed name, and a new
  // logo went unseen for that day, in browsers and at Cloudflare's edge. The server ignores the
  // query; /favicon.ico, which a browser asks for on its own, cannot carry one.
  out = out.replace(/(href|src|srcset|data-light|data-dark)="\/(favicon\.png|favicon-dark\.png|apple-touch-icon\.png|logo\.svg|logo-dark\.svg|boot\.js)"/g,
    (_, attr, file) => `${attr}="/${file}?v=${hash(fs.readFileSync(path.join(here, file)))}"`);
  if (!minify) return { html: out, js, script };
  const r = html.minifySync(out, { minifyJs: false, minifyCss: true, removeComments: true });
  const bad = (r.errors || []).filter(e => e.level === 'Error');
  if (bad.length) throw new Error(`${name}: ${bad.map(e => e.message).join('; ')}`);
  return { html: r.code, js, script };
}

if (process.argv[1] === fileURLToPath(import.meta.url)) {
  const out = process.argv[2] || path.join(here, 'dist');
  fs.mkdirSync(out, { recursive: true });
  fs.writeFileSync(path.join(out, STYLE), buildStyle());
  fs.writeFileSync(path.join(out, 'sw.js'), buildWorker());
  fs.writeFileSync(path.join(out, 'hls.js'), HLS);
  // Served as they are, under the names the pages and the stylesheet use. /favicon.ico is the
  // PNG, for a browser that asks for that on its own; iOS asks for the precomposed touch icon
  // first when the site is added to a home screen (#109). /icon.png is the 2004 icon, which
  // nothing here shows any more but the classic theme.
  for (const [from, to] of [
    ['logo.svg', 'logo.svg'], ['logo-dark.svg', 'logo-dark.svg'],
    ...['signals', 'deadair-on', 'deadair-off'].flatMap(n => [`${n}.svg`, `${n}-dark.svg`]).map(f => [f, f]),
    ['favicon.png', 'favicon.png'], ['favicon.png', 'favicon.ico'], ['favicon-dark.png', 'favicon-dark.png'],
    ['apple-touch-icon.png', 'apple-touch-icon.png'], ['apple-touch-icon.png', 'apple-touch-icon-precomposed.png'],
    ['ipodderx-icon.png', 'icon.png'], ['boot.js', 'boot.js'], ['InterVariable.woff2', 'inter.woff2'], ['Inter-LICENSE.txt', 'Inter-LICENSE.txt'],
  ]) fs.copyFileSync(path.join(here, from), path.join(out, to));
  // The fonts Settings offers besides Inter (#359), with their licences.
  fs.cpSync(path.join(here, 'fonts'), path.join(out, 'fonts'), { recursive: true });
  for (const style of FA_STYLES) {
    fs.mkdirSync(path.join(out, 'icons', style), { recursive: true });
    for (const f of fs.readdirSync(path.join(FA, 'svgs', style))) fs.copyFileSync(path.join(FA, 'svgs', style, f), path.join(out, 'icons', style, f));
  }
  fs.writeFileSync(path.join(out, 'icons', 'index.json'), ICONS);
  fs.copyFileSync(path.join(FA, 'LICENSE.txt'), path.join(out, 'icons', 'LICENSE.txt'));
  for (const name of Object.keys(PAGES)) {
    const { html, js, script } = buildPage(name);
    fs.writeFileSync(path.join(out, name), html);
    fs.writeFileSync(path.join(out, script), js);
  }
  // Each text file compressed once here, as hard as it goes, brotli and gzip beside it, for Caddy
  // to send in its place (#253): smaller than compressing each answer as it goes, and no work then.
  for (const f of fs.readdirSync(out).filter(f => /\.(html|js|css|svg|txt)$/.test(f))) {
    const body = fs.readFileSync(path.join(out, f));
    fs.writeFileSync(path.join(out, f + '.br'), zlib.brotliCompressSync(body, {
      params: { [zlib.constants.BROTLI_PARAM_QUALITY]: zlib.constants.BROTLI_MAX_QUALITY, [zlib.constants.BROTLI_PARAM_SIZE_HINT]: body.length },
    }));
    fs.writeFileSync(path.join(out, f + '.gz'), zlib.gzipSync(body, { level: 9 }));
  }
}