Skip to main content

Never

 In TypeScript, the never type represents the type of values that never occur. It is typically used in two main scenarios:

  1. Function Return Type: When a function never finishes executing (e.g., it always throws an error or enters an infinite loop), TypeScript can infer that the function returns never.


In this example, throwError is a function that explicitly throws an Error. TypeScript infers that this function will never return normally; it will always throw an error. Therefore, the return type is never.

Key Points:

  • Use Case: never is useful for functions that throw errors or enter infinite loops, where the function does not return normally.
  • Inference: TypeScript uses never to narrow down types in conditional type inference and control flow analysis.
  • No Values: Unlike void, which represents the absence of a value, never indicates that a value will never exist (e.g., due to an infinite loop or always throwing an error).

Comments

Post a Comment

Popular posts from this blog

Get OTP from email

/** * Retrieves an OTP from Gmail in a headless tab. * @param {Object} options - The options for the function. * @param {string} options.email - The Gmail email address. * @param {string} options.password - The Gmail password. * @returns {Promise<string | null>} The OTP retrieved from the email. */ export async function getOtpFromGmail ({ email , password , } : { email : string ; password : string ; }) : Promise < string | null > { const { chromium } = require ( "playwright" ); // Launch a headless browser context for Gmail login const browser = await chromium . launch ({ headless : true }); const context = await browser . newContext (); const page = await context . newPage (); await page . goto ( "https://mail.google.com" ); const emailInput = await page . waitForSelector ( "#identifierId" ); await emailInput . fill ( email ); const emailNextButton = await page . wa...
Post a Comment
Read more

Playwright Solution

 There is a web site need to run with browser. and which has zero downtime and alert and notifications pop up too. Third party applications are involved in and need to fix bugs too.What is the solution and how to create a framework for this scenario : need to use playwright as well 1. Understand the Requirements and Challenges: Zero Downtime: Ensure tests do not interrupt the service. Alerts and Notifications: Handle unexpected pop-ups gracefully. Third-Party Integrations: Test interactions with third-party services. Bug Fixing: Implement a process to identify and log bugs efficiently. 2. Set Up the Playwright Framework: Installation: Ensure Playwright is installed and configured. bash Copy code npm install playwright 3. Structure the Test Framework: Test Suites: Organize tests into suites (e.g., smoke tests, regression tests, integration tests). Page Object Model (POM): Use POM to manage page elements and actions. Configuration: Set up configurations for different envir...
Post a Comment
Read more

Challenges

 One of the challenging situations I faced was identifying the correct locators for elements in our Angular application. Despite using developer tools like Chrome DevTools, it was often difficult to pinpoint the exact locators due to the complexity of the application and the dynamic nature of Angular's rendering. To overcome this, I frequently had to review the application's code in Bitbucket to understand the structure and find reliable locators. This approach allowed me to write more robust and reliable tests. Additionally, I communicated with developers to gain insights and confirm my findings, which helped streamline the process." As our application grew, the number of test scripts also increased, making the scripts larger and more chaotic. This was especially true for our end-to-end tests using Playwright and TypeScript. The test scripts became hard to manage and maintain because they contained both the test logic and the test data, leading to a lot of redundancy and ...
Post a Comment
Read more