How to import JSON file to Angular library?

Question

I'm having trouble importing JSON file to my environment file in Angular 7 library. My environment.ts file looks like this:

import firebase from './firebase.json';

export const environment = {
  production: false,
  firebase,
};

And firebase.json:

{
  "apiKey": "",
  "authDomain": "",
  "databaseURL": "",
  "projectId": "",
  "storageBucket": "",
  "messagingSenderId": ""
}

But unfortunately when running ng build it fails:

> [email protected] build <path-to-project>/sdk
> ng build sdk

Building Angular Package
Building entry point 'sdk'
Compiling TypeScript sources through ngc
Bundling to FESM2015

BUILD ERROR
Unexpected token / in JSON at position 0
SyntaxError: Unexpected token / in JSON at position 0
    at JSON.parse (<anonymous>)
    at Object.transform (<path-to-project>/sdk/node_modules/rollup-plugin-json/dist/rollup-plugin-json.cjs.js:18:20)
    at <path-to-project>/sdk/node_modules/rollup/dist/rollup.js:20962:25

Unexpected token / in JSON at position 0
SyntaxError: Unexpected token / in JSON at position 0
    at JSON.parse (<anonymous>)
    at Object.transform (<path-to-project>/sdk/node_modules/rollup-plugin-json/dist/rollup-plugin-json.cjs.js:18:20)
    at <path-to-project>/sdk/node_modules/rollup/dist/rollup.js:20962:25
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] build: `ng build sdk`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] build 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!     xxx/.npm/_logs/2019-04-10T13_40_47_486Z-debug.log

I've tried already:

1) Adding to tsconfig.json

"esModuleInterop": true,
"allowSyntheticDefaultImports": true,
"noImplicitAny": false,

2) Adding typings.d.ts with

declare module '*.json' {
  const value: any;
  export default value;
}

3) Changing import to require

But no luck so far.

My devDependencies include:

"@angular-devkit/build-ng-packagr": "^0.13.8",
"@angular/cli": "~7.3.6",
"@angular/common": "~7.2.0",
"@angular/compiler": "^7.2.12",
"@angular/compiler-cli": "^7.2.12",
...

Answer 1

After a lot of suffering we found that solution here.

It's basically what you've done in the first try, but you need to add one option more.

"resolveJsonModule": true,  
"esModuleInterop": true,
"allowSyntheticDefaultImports": true

Additionally:

"annotateForClosureCompiler": false

Note: for the last prop, that's the same file but instead of adding it to the compilerOptions, add it to angularCompilerOptions