@bestcodetools/jest-tsconfig-paths-mapper/index.js

A utility library for generating Jest's moduleNameMapper based on TypeScript's tsconfig.json path mappings.

const fs = require('fs');
const path = require('path');

function transformPathsToModuleNameMapper(paths, baseUrl) {
  const moduleNameMapper = {};

  for (const [key, value] of Object.entries(paths)) {
    const modulePath = key.replace('/*', '/(.*)').replace(/([$]|[#]|[>]|[:]|[!]|[`]|[´]|[?]|[%]|[&])/g, '[$1]');
    const moduleReplacement = value[0].replace('/*', '/$1');
    const regex = new RegExp(`^${modulePath}$`);

    moduleNameMapper[regex.source] = path.resolve(baseUrl, moduleReplacement);
  }

  return moduleNameMapper;
}

function generateModuleNameMapper(tsconfigPath = 'tsconfig.json') {
  const tsconfigContent = fs.readFileSync(tsconfigPath, 'utf-8');
  const tsconfig = eval(`(() => (\n${tsconfigContent}\n))()`);
  const { paths, baseUrl } = tsconfig.compilerOptions;
  const moduleNameMapper = transformPathsToModuleNameMapper(paths, baseUrl);

  return moduleNameMapper;
}

module.exports = {
  generateModuleNameMapper
};