rollup.config.js

import resolve from "@rollup/plugin-node-resolve";
import commonjs from "@rollup/plugin-commonjs";
import typescript from "@rollup/plugin-typescript";
import dts from "rollup-plugin-dts";
import { terser } from "rollup-plugin-terser";
import peerDepsExternal from 'rollup-plugin-peer-deps-external';

const packageJson = require("./package.json");

export default [
  {
    input: 'src/index.ts',
    output: [
      {
        file: packageJson.main,
        format: "cjs",
        sourcemap: true,
      },
      {
        file: packageJson.module,
        format: "esm",
        sourcemap: true,
      },
    ],
    plugins: [
      peerDepsExternal(),
      resolve(),
      commonjs(),
      typescript({ tsconfig: './tsconfig.json' }),
      terser(),
    ],
    external: ['firebase/app', 'firebase/database']
  },
  {
    input: 'build/types/index.d.ts',
    output: [{ file: 'dist/index.d.ts', format: 'esm' }],
    plugins: [dts()],
  },
];