Implementing an import statement in an Electron renderer script

Question

Implementing an import statement in an Electron renderer script

After following the Electron typescript quick-start code structure by cloning the repo, everything worked fine. However, when attempting to split my code into multiple .ts files and import them into the renderer script, I encountered an issue. Upon adding

import { stuff } from "./otherfile.ts"

at the top of renderer.ts, I received an error message stating

Uncaught ReferenceError: exports is not defined

.

Further investigation revealed that the problem stemmed from the

"module": "commonjs"

setting in tsconfig. Changing this to esnext caused Electron to no longer load the preload script.

Has anyone successfully managed to make Electron and typescript work seamlessly, allowing for the use of import statements across multiple files?

Minimal reproducible example:

File structure:

/dist
/dist/main.js
/dist/preload.js
/dist/renderer.js
/dist/stuff.js
/src
/src/main.ts
/src/preload.ts
/src/renderer.ts
/src/stuff.ts
/index.html

/src/main.ts:

import { ipcMain } from "electron"; // Imports work fine in main
...

ipcMain.on(...

/src/preload.ts:

import { contextBridge, ipcRenderer} from "electron"; // Imports work fine in preload

contextBridge.exposeInMainWorld("my-api", { ....

/src/renderer.ts

import stuff from "./stuff.ts"; // Import fails in renderer (exports is not defined error)

/src/stuff.ts

const stuff = { ... };
export default stuff;

/index.html

<html>
   ...
   <script src="./dist/renderer.js"></script>
 </html>

ts.config:

If I change "module" to "es6", then preload.ts will not load.
If I leave "module" as "commonjs", then imports in renderer.ts do not work.

If I manually add var exports = {} in renderer.js after the TS compilation, I encounter a different error stating, "require is not defined".

javascript typescript electron

Answer 1

Answer №1

Unfortunately, the configuration of the boilerplate does not allow for the use of import/require inside the renderer process.

In order to enable this functionality, you will need to either adjust the security settings in Electron or utilize a transpiler to ensure that the final code executed by the renderer does not contain import/require.

The issue has been confirmed in the electron-quick-start-typescript project, and you can refer to this file for more information.

// This file is necessary to run in the renderer process for the window
// Node.js APIs are not available unless nodeIntegration is set to true in webPreferences
// Use preload.js to enable features required in the renderer process

It's important to note that Node.js APIs, including import and require, are not accessible in this context.

Additionally, when accessing require, a polyfilled version is used if sandboxing is enabled - more details can be found here.

Your alternative, aside from modifying boilerplates, is to access necessary functionalities through the preload script like window.api.yourFunction.

If you require the use of import in the renderer process, consider using a boilerplate that supports transpilation via Webpack.

Two recommended options are:

https://github.com/electron-react-boilerplate/electron-react-boilerplate (highly recommended)
https://github.com/reZach/secure-electron-template

PS - Avoid enabling nodeIntegration when distributing code to maintain Electron's security model!

PPS - Consider using

"module": "ES2020"

, but be aware that it does not address the limitation of import/require within the renderer process.

Answer 2

Unfortunately, the configuration of the boilerplate does not allow for the use of import/require inside the renderer process.

In order to enable this functionality, you will need to either adjust the security settings in Electron or utilize a transpiler to ensure that the final code executed by the renderer does not contain import/require.

The issue has been confirmed in the electron-quick-start-typescript project, and you can refer to this file for more information.

// This file is necessary to run in the renderer process for the window
// Node.js APIs are not available unless nodeIntegration is set to true in webPreferences
// Use preload.js to enable features required in the renderer process

It's important to note that Node.js APIs, including import and require, are not accessible in this context.

Additionally, when accessing require, a polyfilled version is used if sandboxing is enabled - more details can be found here.

Your alternative, aside from modifying boilerplates, is to access necessary functionalities through the preload script like window.api.yourFunction.

If you require the use of import in the renderer process, consider using a boilerplate that supports transpilation via Webpack.

Two recommended options are:

https://github.com/electron-react-boilerplate/electron-react-boilerplate (highly recommended)
https://github.com/reZach/secure-electron-template

PS - Avoid enabling nodeIntegration when distributing code to maintain Electron's security model!

PPS - Consider using

"module": "ES2020"

, but be aware that it does not address the limitation of import/require within the renderer process.

Answer 3

Answer №2

Summary

The error you're encountering seems to stem from mixing CommonJS (CJS) and ES modules (ESM), which are not compatible. Below is a functional example for an Election model, followed by a comparison of CJS and ESM exports and imports.

Solution

Without the code from your original post, I've outlined a potential solution for the issue. Follow these steps:

# Clone this repository
git clone https://github.com/electron/electron-quick-start-typescript
# Navigate to the repository
cd electron-quick-start-typescript
# Install dependencies
npm install

Create a new file as shown below:

// src/otherfile.ts
export const stuff = {
    fullOf: 'stuff'
}

export function shareLocation(loc: string): void {
    console.log(`I was imported by: ${loc}`);
}

In the src/main.ts file, make the following modifications:

// Add import statement at the top
import {stuff, shareLocation} from "./otherfile"

// Add this code at the end of the createWindow() function
shareLocation('main.ts (main.js)');

Run the example with npm start to see

I was imported by: main.ts (main.js)

in your terminal. If you try the same with src/preload.ts, you'll encounter an error due to sandboxing restrictions.

To resolve this, update your src/main.ts file as follows:

// Modify the webPreferences of the new BrowserWindow
const mainWindow = new BrowserWindow({
    height: 600,
    webPreferences: {
      preload: path.join(__dirname, "preload.js"),
      sandbox: false // <=== ADD THIS LINE
    },
    width: 800,
});

Now, your imports should work correctly, displaying

I was imported by: preload.ts (preload.js)

in the electron window console, though be aware that this method is not secure. Consider using IPC instead of disabling the sandbox.

If you're still facing issues, you may be mistakenly using CJS exports with ESM imports. Refer to the next section for a demonstration of the differences between the two.

Comparison: CommonJS (CJS) vs ES modules (ESM)

CommonJS (CJS)

CommonJS was initially used for exporting and requiring modules in Node.js. Below is an example of how to export and import in a CommonJS module:

// example.js
function hello() {
    console.log('World!');
}
module.exports = hello;

And importing the module in another file:

// main.js
const hello = require('./example.js');
hello();

You can export various types using CommonJS, similar to ES modules. Here's an example exporting multiple functions:

// example.js
function hello() {
    console.log('World!');
}
function foo() {
    console.log('Bar!');
}
module.exports = {
    hello,
    foo
};

The same module can be imported as:

// main.js
const {hello, foo} = require('./example.js');
hello();
foo();

ES Module (ESM)

ES modules are the modern way of importing JavaScript code into other modules. An example using ESM is shown below:

// example.js
function hello() {
    console.log('World!');
}
export default hello;

You import the module as follows:

// main.js
import hello from "example";
hello();

If you choose to export multiple items without using default, you'll need to import them differently:

// example.js
function hello() {
    console.log('World!');
}
function foo() {
    console.log('Bar!');
}
export {
    hello,
    foo
}

And import them using object destructuring:

// main.js
import {hello, foo} from "example";
hello();
foo();

For more information on imports, refer to MDN documentation on import and this Free Code Camp Article on JavaScript modules. Additionally, JavaScript Tutorial offers a helpful guide on object destructuring.

Answer 4

Summary

The error you're encountering seems to stem from mixing CommonJS (CJS) and ES modules (ESM), which are not compatible. Below is a functional example for an Election model, followed by a comparison of CJS and ESM exports and imports.

Solution

Without the code from your original post, I've outlined a potential solution for the issue. Follow these steps:

# Clone this repository
git clone https://github.com/electron/electron-quick-start-typescript
# Navigate to the repository
cd electron-quick-start-typescript
# Install dependencies
npm install

Create a new file as shown below:

// src/otherfile.ts
export const stuff = {
    fullOf: 'stuff'
}

export function shareLocation(loc: string): void {
    console.log(`I was imported by: ${loc}`);
}

In the src/main.ts file, make the following modifications:

// Add import statement at the top
import {stuff, shareLocation} from "./otherfile"

// Add this code at the end of the createWindow() function
shareLocation('main.ts (main.js)');

Run the example with npm start to see

I was imported by: main.ts (main.js)

in your terminal. If you try the same with src/preload.ts, you'll encounter an error due to sandboxing restrictions.

To resolve this, update your src/main.ts file as follows:

// Modify the webPreferences of the new BrowserWindow
const mainWindow = new BrowserWindow({
    height: 600,
    webPreferences: {
      preload: path.join(__dirname, "preload.js"),
      sandbox: false // <=== ADD THIS LINE
    },
    width: 800,
});

Now, your imports should work correctly, displaying

I was imported by: preload.ts (preload.js)

in the electron window console, though be aware that this method is not secure. Consider using IPC instead of disabling the sandbox.

If you're still facing issues, you may be mistakenly using CJS exports with ESM imports. Refer to the next section for a demonstration of the differences between the two.

Comparison: CommonJS (CJS) vs ES modules (ESM)

CommonJS (CJS)

CommonJS was initially used for exporting and requiring modules in Node.js. Below is an example of how to export and import in a CommonJS module:

// example.js
function hello() {
    console.log('World!');
}
module.exports = hello;

And importing the module in another file:

// main.js
const hello = require('./example.js');
hello();

You can export various types using CommonJS, similar to ES modules. Here's an example exporting multiple functions:

// example.js
function hello() {
    console.log('World!');
}
function foo() {
    console.log('Bar!');
}
module.exports = {
    hello,
    foo
};

The same module can be imported as:

// main.js
const {hello, foo} = require('./example.js');
hello();
foo();

ES Module (ESM)

ES modules are the modern way of importing JavaScript code into other modules. An example using ESM is shown below:

// example.js
function hello() {
    console.log('World!');
}
export default hello;

You import the module as follows:

// main.js
import hello from "example";
hello();

If you choose to export multiple items without using default, you'll need to import them differently:

// example.js
function hello() {
    console.log('World!');
}
function foo() {
    console.log('Bar!');
}
export {
    hello,
    foo
}

And import them using object destructuring:

// main.js
import {hello, foo} from "example";
hello();
foo();

For more information on imports, refer to MDN documentation on import and this Free Code Camp Article on JavaScript modules. Additionally, JavaScript Tutorial offers a helpful guide on object destructuring.

Answer 5

Answer №3

While Electron isn't fully compatible with ECMAScript modules at this time, your Typescript code can still be very cutting-edge.

OPTION 1 (LOOSE FILES)

To quickly kickstart your renderer process's Typescript code, add the following to your index.html file, similar to this initial sample. Note that this method utilizes node integration, which should be disabled before deploying to production:

<body>
   <div id='root' class='container'></div>

   <script type='text/javascript'>
        require('./built/renderer');
   </script>
</body>

OPTION 2 (BUNDLED)

To eliminate the require statement and align more with Electron security guidelines for SPAs, consider utilizing webpack bundling and referencing built Typescript in the following manner, similar to this updated sample:

<body>
    <div id='root' class='container'></div>

    <script type='module' src='vendor.bundle.js'></script>
    <script type='module' src='app.bundle.js'></script>
</body>

SETTINGS

In my setup, I specify type=commonjs in package.json and module=commonjs in the tsconfig.json file specifically for Electron projects. For non-Electron projects, I opt for ECMAScript module settings for slightly improved output.

The key is to establish a modern code setup that aligns with your preferences, rather than being confined to preset starter projects.

Answer 6

While Electron isn't fully compatible with ECMAScript modules at this time, your Typescript code can still be very cutting-edge.

OPTION 1 (LOOSE FILES)

To quickly kickstart your renderer process's Typescript code, add the following to your index.html file, similar to this initial sample. Note that this method utilizes node integration, which should be disabled before deploying to production:

<body>
   <div id='root' class='container'></div>

   <script type='text/javascript'>
        require('./built/renderer');
   </script>
</body>

OPTION 2 (BUNDLED)

To eliminate the require statement and align more with Electron security guidelines for SPAs, consider utilizing webpack bundling and referencing built Typescript in the following manner, similar to this updated sample:

<body>
    <div id='root' class='container'></div>

    <script type='module' src='vendor.bundle.js'></script>
    <script type='module' src='app.bundle.js'></script>
</body>

SETTINGS

In my setup, I specify type=commonjs in package.json and module=commonjs in the tsconfig.json file specifically for Electron projects. For non-Electron projects, I opt for ECMAScript module settings for slightly improved output.

The key is to establish a modern code setup that aligns with your preferences, rather than being confined to preset starter projects.

Implementing an import statement in an Electron renderer script

Minimal reproducible example:

Answer №1

Answer №2

Summary

Solution

Comparison: CommonJS (CJS) vs ES modules (ESM)

CommonJS (CJS)

ES Module (ESM)

Answer №3

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