build.js

/**
 * This file only purpose is to execute any build related tasks
 */

const { resolve, normalize } = require('path');
const { readFileSync, writeFileSync } = require('fs');

const ROOT = resolve('./');
const DIST = resolve(ROOT, 'dist');
const pkg = require(resolve(ROOT, 'package.json'));

const TYPES_ROOT_FILE = resolve(DIST, normalize(pkg.typings));

main();

function main() {
  writeDtsHeader();
}

function writeDtsHeader() {
  const dtsHeader = getDtsHeader(
    pkg.name,
    pkg.version,
    pkg.author,
    pkg.repository.url,
    pkg.devDependencies.typescript
  );

  prependFileSync(TYPES_ROOT_FILE, dtsHeader);
}

/**
 *
 * @param {string} pkgName
 * @param {string} version
 * @param {string} author
 * @param {string} repoUrl
 * @param {string} tsVersion
 */
function getDtsHeader(pkgName, version, author, repoUrl, tsVersion) {
  const extractUserName = repoUrl.match(/\.com\/([\w-]+)\/\w+/i);
  const githubUserUrl = extractUserName ? extractUserName[1] : 'Unknown';

  return `
// Type definitions for ${pkgName} ${version}
// Project: ${repoUrl}
// Definitions by: ${author} <https://github.com/${githubUserUrl}>
// Definitions: ${repoUrl}
// TypeScript Version: ${tsVersion}
`.replace(/^\s+/gm, '');
}

/**
 *
 * @param {string} path
 * @param {string | Blob} data
 */
function prependFileSync(path, data) {
  const existingFileContent = readFileSync(path, {
    encoding: 'utf8',
  });
  const newFileContent = [data, existingFileContent].join('\n');
  writeFileSync(path, newFileContent, {
    flag: 'w+',
    encoding: 'utf8',
  });
}