TILs - Fueling Curiosity, One Insight at a Time

about ActiveSupport::Notifications there is a railscasts on it http://railscasts.com/episodes/249-notifications-in-rails-3

In javascript generally if you reduce an array it starts from 0th element and goes till the end but if you want to run the reduce from right to left of an array i.e. start from last element and go till the first element use arr.reduceRight

In order to know hierarchy of translations, print defaults here https://github.com/rails/rails/blob/v5.1.4/activemodel/lib/active_model/errors.rb#L405 and see the magic!

flash.now in rails, which allows you to have flash messages which does not persists across subsequent action unlike regular flash i.e it sets a flash message which is available only to the current action and not for next. http://api.rubyonrails.org/v5.1/classes/ActionDispatch/Flash/FlashHash.html#method-i-now

[RealWorld](https://github.com/gothinkster/realworld) is a project that curates a list of implementations of frontends and backends in different frameworks for the same application spec . This is a great way to understand how to build non-trivial features when getting started with a new framework.

ActiveRecord Query method - none. It returns a chainable relation with zero records. Post.none => #<ActiveRecord::Relation []>

active record inspect method is invoked to log the active record collection object to the rails console which by default limits the query by 11 but does not actually limit the query being executed.

Firefox exposes about:crashes url where one can see history of crash reports. Clicking on each crash report takes to mozilla website where one can see crash details

we can tell the browser how to execute the script. By default, browser runs the script immediately by pausing HTML parsing. Else you can specify async or defer with the script tag to either run script asynchronously or defer it until HTML is parsed.

if you are using file-loader with webpack to process your assets and want to serve images from cdn you need to pass that cdn url in `publicPath: '<cdn-url>'

when using webpack-uglify to minify your code if you face a situation where your build fails with syntex error try setting "uglify-js": true this will run all the transformations, however you can use "useBuiltIns": true with that option to only include polyfills for your target browsers

We can use the command docker-compose up -d --no-deps --build <service name> to do a zero downtime upgrade of services inside a running docker-compose stack.

docker system prune -a will free up significant space on your hard disk if you have a lot of stopped docker containers and dangling volumes etc

Cypher language, the SQL equivalent for neo4j graph DB is kickass . It allows users to fetch complex join queries in an intuitive way using pattern matching. https://neo4j.com/developer/cypher/ . Also, neo4j is the DB that helped journalists uncover interesting data relationships that led to paradise papers. This is because neo4j treats relationships as first class citizens and you can query using paths between different data elements. For example, "what is the shortest path between PersonA and PersonB".

staging hunks with fugitive in vim http://vimcasts.org/episodes/fugitive-vim-working-with-the-git-index/