Electron: Unable to load preload script: Resources/app.asar/src/preload.js

I have an electron app that builds and runs in development, but when packaging the app with electron-builder, the preload script is not packaged in the right location.

This is a well documented issue and there are very similar questions here and here for example, but none of the replies or solutions are working in my case.

From my electron.js file:

function createWindow() {
    const mainWindow = new BrowserWindow({
        width: 800,
        height: 600,
        webPreferences: {
            preload: path.join(app.getAppPath(), 'src/preload.js'),
            contextIsolation: true,
        },
    });

    // In production, set the initial browser path to the local bundle generated
    // by the Create React App build process.
    // In development, set it to localhost to allow live/hot-reloading.
    const appURL = app.isPackaged
        ? url.format({
            pathname: path.join(__dirname, 'index.html'),
            protocol: 'file:',
            slashes: true,
        })
        : 'http://localhost:3000';
    mainWindow.loadURL(appURL);

    mainWindow.webContents.openDevTools();
}

My preload script:

const { contextBridge, shell } = require('electron')

contextBridge.exposeInMainWorld(
    'electron',
    {
        openBrowserWindow: (url) => shell.openExternal(url)
    }
)

And my Electron app package.json:

    "build": {
        "extends": null,
        "appId": "com.app",
        "productName": "App",
        "directories": {
            "output": "dist"
        },
        "mac": {
            "target": {
                "target": "pkg",
                "arch": [
                    "universal"
                ]
            },
            "darkModeSupport": "true",
            "extendInfo": "app"
        },
        "pkg": {
            "installLocation": "/Applications",
            "overwriteAction": "upgrade"
        },
        "files": [
            "**",
            "../app/src/*",
            "src/preload.js"
        ],
        "extraResources": [
            "../app/src/*",
            "src/preload.js"
        ],
        "extraFiles": [
            "../app/src/*",
            "src/preload.js"
        ]
    }

Above I have tried to make sure the “src/preload.js” file is copied over in different ways, but I still get the error:

Unable to load preload script: …app/Contents/Resources/app.asar/src/preload.js

Error: Cannot find module ‘…app/Contents/Resources/app.asar/src/preload.js’

The preload script is in fact copied over, but it is not part of the app.asar file. It is copied in to a src folder outside of the Resources folder which contains the app.asar file:

How do I correctly configure electron-builder so this file is in the right location and can be accessed at package runtime?