Allow comments in tsconfig.json files

Previously, if your tsconfig.json file contained a comment (allowed by the
TS compiler) the ts-import-types-cli would throw the following error:

`ts-import-types-cli --project /myproject/tsconfig.json is not a tsconfig.json file`

This is because the node `require` function can only parse valid
(commentless) JSON.

This PR swaps out the use of `require` in favor of directly reading
the file contents, stripping all comments, and only then parsing it
to confirm that it is valid JSON.

Hopefully this will save other users some confusion!

package.json

@@ -10,6 +10,7 @@
   "dependencies": {
     "chalk": "4.1.0",
     "commander": "6.2.0",
+    "strip-json-comments": "^3.1.1",
     "ts-morph": "9.1.0"
   },
   "devDependencies": {

src/bin.ts

@@ -4,6 +4,8 @@ import chalk = require('chalk');
 import program = require('commander');
 import { resolve } from 'path';
 import { tsImportTypes } from '.';
+import stripJsonComments from 'strip-json-comments';
+import fs from 'fs';
 
 const sourcePatterns: string[] = [];
 
@@ -24,7 +26,7 @@ const project = program.project || './tsconfig.json';
 const tsConfigFilePath = resolve(process.cwd(), project);
 
 try {
-  require(tsConfigFilePath);
+  JSON.parse(stripJsonComments(fs.readFileSync(tsConfigFilePath, 'utf8')));
 } catch (err) {
   const message = `ts-import-types-cli --project ${tsConfigFilePath} is not a tsconfig.json file`;
   console.error(chalk.red(message));

yarn.lock

@@ -306,6 +306,11 @@ source-map@^0.6.0:
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
   integrity sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==
 
+strip-json-comments@^3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/strip-json-comments/-/strip-json-comments-3.1.1.tgz#31f1281b3832630434831c310c01cccda8cbe006"
+  integrity sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==
+
 supports-color@^7.1.0:
   version "7.2.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-7.2.0.tgz#1b7dcdcb32b8138801b3e478ba6a51caa89648da"