asset bundle.js 3.19 KiB [emitted] (name: main)
./app.ts 115 bytes [built] [code generated]
./node_modules/a/index.ts 39 bytes [built] [code generated]

ERROR in ./node_modules/a/index.ts
Module build failed (from ../../index.js):
Error: TypeScript emitted no output for node_modules/a/index.ts. By default, ts-loader will not compile .ts files in node_modules.
You should not need to recompile .ts files there, but if you really want to, use the allowTsInNodeModules option.
See: https://github.com/Microsoft/TypeScript/issues/12358
    at makeSourceMapAndFinish (dist/index.js:55:18)
    at successLoader (dist/index.js:42:5)
    at Object.loader (dist/index.js:23:5)
 @ ./app.ts 3:8-20

webpack compiled with 1 error