Function loadESMFromCJS

lib/internal/modules/cjs/loader.js:1703–1766

* Resolve and evaluate it synchronously as ESM if it's ESM. * @param {Module} mod CJS module instance * @param {string} filename Absolute path of the file. * @param {string} format Format of the module. If it had types, this would be what it is after type-stripping. * @param {string} source Sour

(mod, filename, format, source)

 * @param {string} source Source the module. If it had types, this would have the type stripped.
 */
function loadESMFromCJS(mod, filename, format, source) {
  const cascadedLoader = require('internal/modules/esm/loader').getOrInitializeCascadedLoader();
  const isMain = mod[kIsMainSymbol];
  if (isMain) {
    require('internal/modules/run_main').runEntryPointWithESMLoader((cascadedLoader) => {
      const mainURL = pathToFileURL(filename).href;
      return cascadedLoader.import(mainURL, undefined, { __proto__: null }, undefined, true);
    });
    // ESM won't be accessible via process.mainModule.
    setOwnProperty(process, 'mainModule', undefined);
  } else {
    const parent = mod[kLastModuleParent];

    requireModuleWarningMode ??= getOptionValue('--trace-require-module');
    if (requireModuleWarningMode) {
      let shouldEmitWarning = false;
      if (requireModuleWarningMode === 'no-node-modules') {
        // Check if the require() comes from node_modules.
        if (parent) {
          shouldEmitWarning = !isUnderNodeModules(parent.filename);
        } else if (mod[kIsCachedByESMLoader]) {
          // It comes from the require() built for `import cjs` and doesn't have a parent recorded
          // in the CJS module instance. Inspect the stack trace to see if the require()
          // comes from node_modules as a direct call and reduce the noise.
          shouldEmitWarning = !isInsideNodeModules();
        }
      } else {
        shouldEmitWarning = true;
      }
      if (shouldEmitWarning) {
        let messagePrefix;
        if (parent) {
          // In the case of the module calling `require()`, it's more useful to know its absolute path.
          let from = parent.filename || parent.id;
          // In the case of the module being require()d, it's more useful to know the id passed into require().
          const to = mod.id || mod.filename;
          if (from === 'internal/preload') {
            from = '--require';
          } else if (from === '<repl>') {
            from = 'The REPL';
          } else if (from === '.') {
            from = 'The entry point';
          } else {
            from &&= `CommonJS module ${from}`;
          }
          if (from && to) {
            messagePrefix = `${from} is loading ES Module ${to} using require().\n`;
          }
        }
        emitExperimentalWarning('Support for loading ES Module in require()',
                                messagePrefix,
                                undefined,
                                parent?.require);
        requireModuleWarningMode = true;
      }
    }
    const {
      wrap,