fix: make tsconfig-paths work with comments in tsconfig.json

[RafaelKr]

When you run tsc --init it creates a tsconfig.json which includes two types of comments:

1. // single line
2. /* multiline */

When using require() to load this tsconfig.json with comments it throws an error:
SyntaxError: /path/to/tsconfig.json: Unexpected token / in JSON at position 29

This is why tsconfig-paths uses it's own loadTsconfig function to parse that JSON file.
So we can simply use that instead of require()

tsconfig.json from "tsc --init"

{
  "compilerOptions": {
    /* Visit https://aka.ms/tsconfig.json to read more about this file */

    /* Basic Options */
    // "incremental": true,                   /* Enable incremental compilation */
    "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
    // "lib": [],                             /* Specify library files to be included in the compilation. */
    // "allowJs": true,                       /* Allow javascript files to be compiled. */
    // "checkJs": true,                       /* Report errors in .js files. */
    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
    // "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
    // "sourceMap": true,                     /* Generates corresponding '.map' file. */
    // "outFile": "./",                       /* Concatenate and emit output to single file. */
    // "outDir": "./",                        /* Redirect output structure to the directory. */
    // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
    // "composite": true,                     /* Enable project compilation */
    // "tsBuildInfoFile": "./",               /* Specify file to store incremental compilation information */
    // "removeComments": true,                /* Do not emit comments to output. */
    // "noEmit": true,                        /* Do not emit outputs. */
    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */

    /* Strict Type-Checking Options */
    "strict": true,                           /* Enable all strict type-checking options. */
    // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
    // "strictNullChecks": true,              /* Enable strict null checks. */
    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
    // "strictBindCallApply": true,           /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
    // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
    // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
    // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */

    /* Additional Checks */
    // "noUnusedLocals": true,                /* Report errors on unused locals. */
    // "noUnusedParameters": true,            /* Report errors on unused parameters. */
    // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */

    /* Module Resolution Options */
    // "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
    // "typeRoots": [],                       /* List of folders to include type definitions from. */
    // "types": [],                           /* Type declaration files to be included in compilation. */
    // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
    "esModuleInterop": true,                  /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
    // "allowUmdGlobalAccess": true,          /* Allow accessing UMD globals from modules. */

    /* Source Map Options */
    // "sourceRoot": "",                      /* Specify the location where debugger should locate TypeScript files instead of source locations. */
    // "mapRoot": "",                         /* Specify the location where debugger should locate map files instead of generated locations. */
    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */

    /* Experimental Options */
    // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
    // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */

    /* Advanced Options */
    "skipLibCheck": true,                     /* Skip type checking of declaration files. */
    "forceConsistentCasingInFileNames": true  /* Disallow inconsistently-cased references to the same file. */
  }
}

Maybe Related:
#150
#170
#291
vercel/vercel#2832

[RafaelKr]

I also tried to add a test, but I couldn't run the tests locally

$ npm run test         

> @vercel/ncc@0.24.0 test /home/rafael/coding/github/ncc
> node --expose-gc --max_old_space_size=3072 node_modules/.bin/jest

 FAIL  test/index.test.js
  ● Test suite failed to run

    Cannot find module '../' from 'test/index.test.js'

      2 | const { fork } = require("child_process");
      3 | const coverage = global.coverage;
    > 4 | const ncc = coverage ? require("../src/index") : require("../");
        |                                                  ^
      5 | 
      6 | for (const unitTest of fs.readdirSync(`${__dirname}/unit`)) {
      7 |   it(`should generate correct output for ${unitTest}`, async () => {

      at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:307:11)
      at Object.<anonymous> (test/index.test.js:4:50)

 FAIL  test/watcher.test.js
  ● Test suite failed to run

    Cannot find module '../' from 'test/watcher.test.js'

      1 | const path = require('path');
    > 2 | const ncc = global.coverage ? require("../src/index") : require("../");
        |                                                         ^
      3 | const fs = require('fs');
      4 | 
      5 | // Based on the NodeWatchFileSystem class at:

      at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:307:11)
      at Object.<anonymous> (test/watcher.test.js:2:57)

Test Suites: 2 failed, 2 total
Tests:       0 total
Snapshots:   0 total
Time:        0.781 s, estimated 232 s
Ran all test suites.
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! @vercel/ncc@0.24.0 test: `node --expose-gc --max_old_space_size=3072 node_modules/.bin/jest`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the @vercel/ncc@0.24.0 test script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/rafael/.npm/_logs/2020-09-12T22_33_44_374Z-debug.log

[styfle]

Thanks!

[RafaelKr]

@styfle Thanks for merging! Do you know when this will be released?

[RafaelKr]

Thanks for the quick release!