When using TypeScript declarations with Puppeteer's exposeFunction method and Webpack, you need to ensure that TypeScript recognizes the exposed functions correctly. This involves creating type declarations for the functions and ensuring that the exposed functions have the correct types in your TypeScript code.

Here's a step-by-step guide on how to use TypeScript declarations with Puppeteer's exposeFunction and Webpack:

Step 1: Create TypeScript Declarations Create a file (e.g., customTypes.d.ts) in your project to define TypeScript declarations for the functions you want to expose. For example:

// customTypes.d.ts declare global { interface Window { myExposedFunction: (arg: string) => void; } }

Step 2: Add the TypeScript Declarations to tsconfig.json Make sure your tsconfig.json includes the customTypes.d.ts file in the include or files section. This step is crucial to ensure that TypeScript recognizes the global interface declarations.

{ "compilerOptions": { // Your existing compiler options... }, "include": [ "src", // or your source folder "customTypes.d.ts" ] }

Step 3: Use exposeFunction in Puppeteer In your Puppeteer script, use the exposeFunction method to expose the JavaScript function. Ensure that the function is also added to the window object to make it accessible to TypeScript.

import puppeteer from 'puppeteer'; async function runPuppeteer() { const browser = await puppeteer.launch(); const page = await browser.newPage(); // Expose the function to the page await page.exposeFunction('myExposedFunction', (arg: string) => { console.log('Received argument:', arg); }); await page.goto('https://example.com'); // Call the exposed function in the browser await page.evaluate(() => { (window as any).myExposedFunction('Hello from the page!'); }); await browser.close(); } runPuppeteer();

Step 4: Build with Webpack When using Webpack to bundle your TypeScript code, make sure you have the necessary configurations to handle TypeScript declarations correctly.

Ensure that you have the appropriate TypeScript loader for Webpack, such as ts-loader, and that the tsconfig.json is correctly configured to include the customTypes.d.ts file.

Additionally, if you are using any additional Webpack plugins or configurations, make sure they do not interfere with the TypeScript type checking or declaration handling.

By following these steps, you should be able to use TypeScript declarations with Puppeteer's exposeFunction method and Webpack. This will enable you to work with type-checked exposed functions when interacting between Puppeteer and your page scripts.

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