jest: javascript testing framwork

"Jester's privilege is the ability and right of a jester to talk and mock freely without being punished."

In this post, I will be playing with some of the tools under a jest.js' belt that helps him deploy his privilege. 

A basic building block of the jest.js program is a test.

A test is a series or a singular combination of expectation followed by a matcher.

The simplest way to explicitly specify an expectation is using the expect method.



When Jest runs, it tracks all the failing matchers and prints out error messages based on that.

Popular posts from this blog

What really is a Hypertext?

Image
The word 'hypertext' appears almost always among Web jargon that is abbreviated such as HTTP, and HTML. What is it? How significant is Hypertext to the Internet? 🔦 Background A lot of us will never be able to fully appreciate the effects of implementing Hypertext as an Information Management System on the Internet. Before hypertext became popular the Internet was just a vast repo of scattered & isolated information items(or objects) that was hard to search & navigate. Hypertext brought  order & organization to an Internet that was difficult to use and disorganized due to its distributed & decentralized nature. P.S Hypertext comes under the field of Information Mapping which then comes under the field of Information Management. 💡What was the necessity for Hypertext? The first 'browser' was developed to combat information loss at an org due to people leaving & make information discovery possible for new people joining the org. The org here was CE...
read

Crypto crypto everywhere but not a token to bet your life on

Over 7000 cryptocurrencies are in existence as of today - which one will survive?  Let's make an attempt to weed out some noise from the crypto landscape so that we can focus on the signals.  Firstly,  Metcalfe's Law  states that the value of a network is proportional to the square of the number of its users. This will be a good indicator to predict less erroneously the one crypto that will rule out the rest. Scarcity is another metric. Scarcity leads to novelty. Humans love to possess novel things. So cryptos leaning to scarcity in the near or far future could be a way to go. The metric to go by, in this case, would be Maximum Supply . It is the best approximation of the maximum amount of coins that will ever exist in the lifetime of the cryptocurrency. The total number of BTC will never exceed 21 million. The hard cap is a limit that is written in Bitcoin's source code and enforced by network nodes.
read

Browser Rendering Phase

Image
A browser render at 60fps. We often call it framerate . A second is 1000 millisecond. That's ~16.66ms spent to render each frame. If this rate is maintained by the browser everything on a website will seem silky smooth. When this framerate drops, users experience jank. A jank is when there is any stuttering or choppiness in motion on screen - for e.g., scrolling, transitions, animations. This negatively affects user experience (UX). Jank is the result of the browser not being able to budget its compute within the 16 ms for each frame. To understand how tight that time window here is a fun fact. The duration of a blink is on average is 100–150 milliseconds according to this  UCL research . That is way less time than a blink of an eye. What's going on behind each frame render? In this post, I attempt at an oversimplified articulation of 6 stage before a frame is rendered. I try to walk through the entire length of that 'rendering' process without getting into too many de...
read