rollup.config.js

import multiInput from "rollup-plugin-multi-input";
import packageJson from "./package.json";
import esbuild from "rollup-plugin-esbuild";
import typescript from "@rollup/plugin-typescript";

const globals = {
  ...packageJson.dependencies,
  ...packageJson.devDependencies,
};

/** @type {import('rollup').RollupOptions} */
const baseConfig = {
  input: ["src/**/*.ts"],
  output: {
    dir: "dist",
    sourcemap: true,
  },
  plugins: [
    esbuild(),
    typescript({
      emitDeclarationOnly: true,
      sourceMap: false,
    }),
  ],
  external: [
    ...Object.keys(globals),
    "@sveltejs/kit/assets/runtime/app/navigation",
    "@sveltejs/kit/assets/runtime/app/stores",
  ],
};

/** @type {Array.<import('rollup').RollupOptions>} */
export default [
  {
    ...baseConfig,
    output: {
      ...baseConfig.output,
      format: "cjs",
    },
    plugins: [...baseConfig.plugins, multiInput()],
  },
  {
    ...baseConfig,
    output: {
      ...baseConfig.output,
      format: "esm",
    },
    plugins: [
      ...baseConfig.plugins,
      multiInput({
        /** @param {string} output */
        transformOutputPath: (output) =>
          `${output.split(".").slice(0, -1).join(".")}.esm.${output.split(".").slice(-1)}`,
      }),
    ],
  },
];