TypeError: fs__WEBPACK_IMPORTED_MODULE_0___default(...).readFileSync is not a function - Node, Electron, Vue App - fs is undefined

Question

I am trying to programm an app that generates JSON file from a CSV file but i am having problems with reading the CSV-file. Here is the code from my vuex store. Only the imports and the generateJSON() function should be the important parts.

import { createStore } from "vuex";
import fs from "fs";

export const store = createStore({
  state: {
    filePath: "",
    datasets: [],
  },
  getters: {
    filePath: (state) => state.filePath,
    datasets: (state) => state.datasets,
  },
  mutations: {
    setFilePath(state, path) {
      console.log("Path has been set to: " + path);
      state.filePath = path;
    },
    setDatasets(state, path) {
      console.log("Datasets have been set");
      state.filePath = path;
    },
  },
  actions: {
    generateJSON({ getters, commit }) {
      console.log("started JSON generation process");
      const filePath = getters.filePath;

      const allFileContents = fs.readFileSync(filePath + "", "utf-8");
      allFileContents.split(/\r?\n/).forEach((line) => {
        console.log(`Line from file: ${line}`);
      });

      commit("setDatasets", "test data");
    },
  },
});

For some reason i keep getting this Error:

Uncaught (in promise) TypeError: fs__WEBPACK_IMPORTED_MODULE_0___default(...).readFileSync is not a function
    at Store.generateJSON (index.js?68eb:28)
    at Array.wrappedActionHandler (vuex.esm-bundler.js?03c9:305)
    at Store.dispatch (vuex.esm-bundler.js?03c9:1031)
    at Store.boundDispatch [as dispatch] (vuex.esm-bundler.js?03c9:914)
    at Proxy.onChange (DragArea.vue?2196:47)
    at Proxy.drop (DragArea.vue?2196:60)
    at onDrop._cache.<computed>._cache.<computed> (DragArea.vue?2196:8)
    at callWithErrorHandling (runtime-core.esm-bundler.js?d2dd:193)
    at callWithAsyncErrorHandling (runtime-core.esm-bundler.js?d2dd:201)
    at HTMLDivElement.invoker (runtime-dom.esm-bundler.js?2725:671)

Eventhough fs is definitely defined at the top of the programm.

I read up on the issue and already tried different ways of importing the fs-module. This didn't solve my problem.