Unable to import local files

This is a Bug Report

Description

When I import my local files I have to specify the file extension otherwise webpack throws an error

import { Student } from "./student.ts"; Works fine 👍

import { Student } from "./student"; Throws error: ERROR in ./handler.ts Module not found: Error: Can't resolve './student' in '/Users/edwardbyrne/Desktop/my-service' @ ./handler.ts 3:16-36

Very strange!

Additional Data

webpack.config.js
const path = require('path');
// eslint-disable-next-line import/no-unresolved
const slsw = require('serverless-webpack');

module.exports = {
  entry: slsw.lib.entries,
  output: {
    libraryTarget: 'commonjs',
    path: path.join(__dirname, '.webpack'),
    filename: '[name].js',
  },
  target: 'node',
  module: {
    loaders: [
      { test: /\.ts(x?)$/, loader: 'ts-loader' },
    ],
  },
};

[franciscocpg]

@HyperBrain https://github.com/serverless/serverless/pull/4281

[HyperBrain]

Merged 😄