The code under lib/internal/modules/esm, a.k.a. the ESM loader, contains many functions that are async. We should refactor as many of these as possible, ideally all of them, to be synchronous. This should improve the performance of evaluating ESM code, bringing it roughly on par with the speed of running CommonJS code.

Longer term, once the ESM loader is synchronous and we land the synchronous module customization hooks, we could deprecate monkey-patching the CommonJS loader and merge together the CommonJS and ESM loaders, eliminating duplication: #50356.

This issue will track our progress syncifying the various files and functions of the ESM loader until we can get as much of it to be as synchronous as possible.

The files to be updated, all underlib/internal/modules:

• run_main.js: asyncRunEntryPointWithESMLoader
• esm/fetch_module.js: fetchWithRedirects
• esm/fetch_module.js: isLocalAddress
• esm/hooks.js: Hooks class (the async methods here probably don’t need updating as they will be removed once we migrate to the synchronous customization hooks)
• esm/hooks.js: nextHookFactory
• esm/load.js: getSource esm: syncify default path of ModuleLoader.load #57419
• esm/load.js: defaultLoad esm: syncify default path of ModuleLoader.load #57419
• esm/loader.js: ModuleLoader.eval
• esm/loader.js: ModuleLoader.getModuleJobForImport
• esm/loader.js: ModuleLoader.loadAndTranslate
• esm/loader.js: ModuleLoader.import
• esm/loader.js: ModuleLoader.load
• esm/module_job.js: ModuleJob._link
• esm/module_job.js: ModuleJob._instantiate
• esm/module_job.js: ModuleJob.run
• esm/module_job.js: ModuleJobSync.run
• esm/translators.js: wasm handler, via translators.set('wasm', ...
• esm/utils.js: importModuleDynamicallyCallback
• esm/utils.js: initializeHooks (might not need updating as we will remove this once the synchronous customization hooks land
• esm/worker.js: customizedModuleWorker (might not need updating as we will remove this once the synchronous customization hooks land
• esm/worker.js: handleMessage (might not need updating as we will remove this once the synchronous customization hooks land

@nodejs/loaders @mcollina @JakobJingleheimer @joyeecheung