require('file.json') doesn't work in webpack

I've a JSON file which I want to load in a Typescript class. Normally a syntax for that is

let json = require('file.json');
// Use of json file in TS class

This works perfectly fine under normal circumstances. But when I try to compile entire code with webpack, code doesn't work. I see the output code is replaced with following

var json = __webpack_require__(2);

This doesn't make much sense. Can somebody tell me what's going on under the hood and how to fix this issue?