Techniques to test your web page using Node js selenium web driver.

await driver.get(‘');

await driver.wait(until.elementLocated(By.xpath(“//input[@placeholder=’’]”),2000));

Note: 2000 is milliseconds it can wait for max.

await element.sendKeys(‘my name);

let e3 = await driver.findElement(By.xpath(“//div[@data-testid=’login’]”));


await driver.wait(until.elementLocated(By.xpath(“//*[text()=’POS’]”),120000));

await driver.wait(until.elementLocated(By.xpath(“//*[text()=’Coke’]”),120000))…

Why, How, What, Where!


NoSQL databases are purpose built for specific data models and have flexible schemas for building modern applications. NoSQL databases are widely recognized for their ease of development, functionality, and performance at scale.

At TILL, we use a combination of NoSQL and relational databases depending on our…

The optional chaining operator (?.) permits reading the value of a property located deep within a chain of connected objects without having to expressly validate that each reference in the chain is valid.

Note: The ?. operator functions similarly to the . chaining operator, except that instead of causing an error if a reference is nullish (null or undefined), the expression short-circuits with a return value of undefined. When used with function calls, it returns undefined if the given function does not exist.

This results in shorter and simpler expressions when accessing chained properties when the possibility exists that a reference may be missing. It can also be helpful while exploring the content of an object when there’s no known guarantee as to which properties are required.

Problem domain: Analytics

You define jobs in AWS Glue to accomplish the work that’s required to extract, transform, and load (ETL) data from a data source to a data target. You typically perform the following actions:

  • For data store sources, you define a crawler to populate your AWS Glue Data…

Problem domain:
Asynchronous Communication in Microservice World

What does it offer?
Event ingestion from many sources(AWS services or Third party)
Event delivery (
Targets can be AWS service or Third party)
Event security
Event access Authorization
Event consumption Error handling

Connect data from SaaS apps
EventBridge ingests data from supported SaaS applications…

Some basic concepts:

a) How to represent time in an universal format?
Answer: As a number
Epoch time — The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970.
Ex: 1606982441

In Nodejs,

let dateNow =;

  • A producer is a user application that sends messages.
  • A queue is a buffer that stores messages.
  • A consumer is a user application that receives messages.

The core idea in the messaging model in RabbitMQ is that the producer never sends any messages directly to a queue. …

Very good blog to read about the life cycle of messages in SQS,a%20large%20number%20of%20messages.&text=There%20is%20no%20concept%20of,visibility%20timeout%20provided%20by%20SQS.

Important points:

  1. Delivery of Messages can be delayed
  2. Messages have an expiry
  3. Dead letter queues if unable to process a message. Unable to process is identified by number of retries to read a message.
  4. Once a message is being read by a consumer, this message shouldn’t be processed by another service at the same time. So when a message is being read, you can configure SQS so that same message wont be read by multiple consumers. This concept is called as Visibility Timeout.

Arun Rajeevan

Suffering from Knowledge Quest

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