learnGitBranching-mirror/scripts/generateLevelManifest.js

/**
 * Generates src/levels/generated/manifest.js.
 *
 * The full level definitions (dialog copy, trees, solutions) for every locale
 * are by far the largest part of the bundle. The browser only needs a tiny
 * metadata slice up front (id / name / hint) to render the level map; the heavy
 * definition is code-split behind `load()` and fetched when a level is opened.
 *
 * Source of truth is src/levels/index.js (levelFiles) plus the level modules
 * themselves, so this must run before `dev`, `build` and `test`.
 */
const { writeFileSync, mkdirSync } = require('fs');
const { join, dirname } = require('path');

const { levelFiles, levelSequences } = require('../src/levels/index');

const OUT_DIR = join(__dirname, '..', 'src', 'levels', 'generated');
const OUT_FILE = join(OUT_DIR, 'manifest.js');

// Relative to src/levels/generated/, where the manifest lives.
function importPath(modulePath) {
  return '../' + modulePath.replace(/^\.\//, '') + '.js';
}

const sequences = {};
Object.keys(levelFiles).forEach((sequenceName) => {
  sequences[sequenceName] = levelSequences[sequenceName].map((level, index) => {
    const entry = {
      id: sequenceName + String(index + 1),
      index,
      sequenceName,
      name: level.name,
    };
    return entry;
  });
});

let out = '// AUTO-GENERATED by scripts/generateLevelManifest.js -- do not edit.\n';
out += "'use strict';\n\n";
out += 'exports.sequences = {\n';
Object.keys(sequences).forEach((sequenceName) => {
  out += '  ' + JSON.stringify(sequenceName) + ': [\n';
  sequences[sequenceName].forEach((entry, index) => {
    const spec = importPath(levelFiles[sequenceName][index]);
    out += '    { id: ' + JSON.stringify(entry.id) +
      ', index: ' + entry.index +
      ', sequenceName: ' + JSON.stringify(entry.sequenceName) +
      ', name: ' + JSON.stringify(entry.name);
    out += ', load: function () { return import(' + JSON.stringify(spec) + '); } },\n';
  });
  out += '  ],\n';
});
out += '};\n';

mkdirSync(OUT_DIR, { recursive: true });
writeFileSync(OUT_FILE, out);

const count = Object.keys(sequences).reduce((n, s) => n + sequences[s].length, 0);
console.log('Generated ' + OUT_FILE + ' (' + count + ' levels, ' +
  Math.round(out.length / 1024) + ' KB)');