Node 17 custom ESM loader (TypeScript and paths rewrite)

README.md

Allows to use ts-node and tsconfig-paths with ES Modules. Works only in Node 17+.

WARNING: This Node API (custom ESM loaders) is currently being redesigned and will still change [>]

Usage: Pass --loader ./loader.js to Node: node --loader ./loader.js index.ts

Example with Webpack: node --loader ./loader.js node_modules/webpack/bin/webpack serve -c build/config/development.ts

This allows to run .ts files and import using aliases defined in tsconfig.json paths.

loader.js

import {load as tsLoad, resolve as tsResolve} from "ts-node/esm";
import tsConfigPaths from "tsconfig-paths";
import {pathToFileURL} from "url";

const tsconfig = tsConfigPaths.loadConfig();
const matchPath = tsConfigPaths.createMatchPath(tsconfig.absoluteBaseUrl, tsconfig.paths);

export function resolve(specifier, context, defaultResolve) {
  let mappedSpecifier = matchPath(specifier);
  if (mappedSpecifier) {
    mappedSpecifier += ".ts";
    specifier = pathToFileURL(mappedSpecifier).href;
  }

  return tsResolve(specifier, context, defaultResolve);
}

export function load(url, context, defaultLoad) {
  return tsLoad(url, context, defaultLoad);
}