What is the best way to bring in local modules within the browser environment using Playwright?

Question

What is the best way to bring in local modules within the browser environment using Playwright?

Let me illustrate what I am attempting to achieve:

../src/Foo/Bar.ts represents a local TypeScript file

This particular file contains code that is designed to function within a browser environment (it utilizes WebSockets), and therefore needs to be executed in page.evaluate

page.evaluate( async () => {
    const { namedExportExample } = await import('../src/Foo/Bar');

    // ...
});

Upon running this, I encounter the error message

page.evaluate: TypeError: Failed to resolve module specifier

. This outcome was expected, as it seems unrealistic for the browser to evaluate such an import. Is there a potential workaround or solution available for this scenario?

typescript playwright sveltekit dynamic-import

Answer 1

Answer №1

Is it possible for the browser to evaluate that import? I'm unsure, but I am curious if there is a way to achieve this.

You cannot directly import modules as explained by @max-schmitt. However, Playwright's "Context" offers a solution by allowing you to inject new functions into the browser instance.

browserContext.exposeFunction(name, callback)

For example:

import * as crypto from "node:crypto" 

const browser = await chromium.launch(...)
const context = await browser.newContext()
    
// !!! Exposing a new function !!!
await context.exposeFunction("sha256", text => crypto.createHash('sha256').update(text).digest("hex")) 

const page = await context.newPage()
await page.goto(URL)

...
await someBox.evaluate((box : HTMLElement) => {
  console.log("!!!", window["sha256"]) // available !!!
  ...
})

Answer 2

Is it possible for the browser to evaluate that import? I'm unsure, but I am curious if there is a way to achieve this.

You cannot directly import modules as explained by @max-schmitt. However, Playwright's "Context" offers a solution by allowing you to inject new functions into the browser instance.

browserContext.exposeFunction(name, callback)

For example:

import * as crypto from "node:crypto" 

const browser = await chromium.launch(...)
const context = await browser.newContext()
    
// !!! Exposing a new function !!!
await context.exposeFunction("sha256", text => crypto.createHash('sha256').update(text).digest("hex")) 

const page = await context.newPage()
await page.goto(URL)

...
await someBox.evaluate((box : HTMLElement) => {
  console.log("!!!", window["sha256"]) // available !!!
  ...
})

Answer 3

Answer №2

When working with Playwright, it's important to understand that Playwright scripts operate within the Playwright environment, while page scripts run in the browser page environment. These environments function independently, as they are executed in separate virtual machines, processes, and potentially on different machines.

If you encounter a scenario where you need to import a file into the page, remember that the page does not have knowledge of where to find that file. To address this, you will need to convert your function into a string and transmit it to the page for evaluation.

For further details, you can refer to:

Answer 4

When working with Playwright, it's important to understand that Playwright scripts operate within the Playwright environment, while page scripts run in the browser page environment. These environments function independently, as they are executed in separate virtual machines, processes, and potentially on different machines.

If you encounter a scenario where you need to import a file into the page, remember that the page does not have knowledge of where to find that file. To address this, you will need to convert your function into a string and transmit it to the page for evaluation.

For further details, you can refer to:

What is the best way to bring in local modules within the browser environment using Playwright?

Answer №1

For example:

Answer №2

Similar questions

Retrieve the svg file either from the DOM or the Object element

Using react-google-charts to create visually appealing dual-Y stacked bar charts

I encountered an issue with Cypress when attempting to utilize a custom command. The error message "TypeError cy.login is not a function" keeps popping up. Any suggestions on how to resolve this

Looking to utilize Axios in React to make API calls based on different categories upon clicking - how can I achieve this?

Understanding Typescript typings and npm packages can greatly improve your development workflow

Specify that a function is adhering to an interface

typescript What is the best approach to searching within a nested array?

Running an HTTP request conditionally within combineLatest

What setting should I adjust in order to modify the color in question?

Angular two - Communication between parent and children components using a shared service

The power of negative multiplication in TypeScript and React

Having trouble with errors when trying to implement react-router-v6 with typescript

Is it possible for TypeScript to preserve the return type while consolidating multiple classes or objects of functions in a reducer method?

What prevents TypeScript from allowing an async function to return a combination of type T or Promise<T>?

Clicking on an Angular routerLink that points to the current route does not function unless the page is re

Invoking a Typescript function from the Highcharts load event

Guide to releasing a NestJs library on npm using the nrwl/nx framework

Implementing a boolean toggle method in Typescript for a class property

What method can be used to specify a function of any signature that returns a particular type in programming?

Nested self-referencing in Typescript involves a structure where