There is Published property in Details/Stats section.

has a timer with interval of 1000ms

Nothing in description about that.

in the componentDidMount method you initialize a timer

In componentWillMount rather.

Tests with long targets and relatively short word lists?

Read instructions carefully:

if functions mean or variance have as parameter town a city which has no records return -1

Previously asked by bel but I will raise this as issue:

1. When todo list is empty and there is more than one item to add, you expect only first one to be added. Bug?
2. Such case appear only in random tests, so it is possible to avoid it.

Maybe what is inside reversed(q) should be given as function argument? Now it's too similar to other reverse list katas.

It is possible to call sort without using 's' letter.

What is the point of posting this in Discourse section?

There are many dirty tricks to make your code execution faster. Most of which you will never use in production code. People will start upvoting fastest answers as "Best Practice" and people who learn to code will pick up some bad habbits. The only thing that could work is a special category of katas, purposely curated for execution time optimizations with solutions showed from fastest to slowest.

• Imports should be visually separated from the rest of the code.
• There is already digits constant definied in string standard library.
• 'newword' -> 'new_word'

Assigning a lambda expression to a variable is an anti-pattern.