I'm having some issues when I use a Proxy with the puppeteer library.

This is the class definition

const puppeteer = require("puppeteer");

class CustomPage {
  static async build() {
    const browser = await puppeteer.launch({ headless: false });
    const page = await browser.newPage();
    const customPage = new CustomPage(page);
    const superPage = new Proxy(customPage, {
      get: function (target, property) {
        //pay attention to the order between browser and page because of an issue
        return customPage[property] || browser[property] || page[property];
      }
    });
    console.log("superPage in CustomPage class definition", superPage);
    return superPage;
  }
  constructor(page) {
    this.page = page;
  }
}

module.exports = CustomPage;

And this is the error that I get when I run it

 TypeError: Cannot read private member from an object whose class did not declare it

       7 | beforeEach(async () => {
       8 |   page = await Page.build();
    >  9 |   await page.goto("localhost:3000");
         |              ^
      10 | });

Could you please help me with that?

CodePudding user response：

Looks like goto function calls some properties that declared as private like this #someProperty. Proxies and private properties cannot work together.

Here is the issue about that: https://github.com/tc39/proposal-class-fields/issues/106

In short you have to abandon the idea of using one of them: proxies or private properties. In your case since private properties are part of puppeteer you'll have to abandon proxy. I think it can be replaced with some wrapper. Why would you want your CustomPage to behave both as puppeteer.Browser and puppeteer.Page instances? Tell me more about what you're trying to achieve, I'd like to help.