TIL

Vim has commands built-in to increment and decrement numbers: CTRL-A and CTRL-X, respectively. Combining this with a macro was a technique we tried today to build a large database migration. We ended up finding a more efficient solution, but it’s still a very magical key combination. Check out :help CTRL-A for more info. h/t Josh Branchaud

We had a testing issue this week when a button’s text save changes! was rendering as SAVE CHANGES!, due to the CSS property text-transform: uppercase. How do you test that? One technique is to use RSpec’s match method, and include case insensitivity with i (explored earlier here): > button_text = "foo" => "foo" > expect(button_text).to match("FOO") RSpec::Expectations::ExpectationNotMetError: expected "foo" to match "FOO" # stuff > expect(button_text).to match(/FOO/i) => true We ultimately hard coded the expectation to match("FOO"), because allowing fOo and FoO seemed too permissive. But it remains an option.

Today I found a way to assert that an edit form’s inputs include a record’s saved data. I think it strikes a good balance between broad and narrow scope. # spec/features/user_edits_kit_spec.rb within 'form' do expect(page).to have_selector("input[value='Default copy.']") end This asserts that some content is inside an input field in the form, rather than just anywhere on the page. You can narrow the scope as needed.

Today I was cleaning up a test with an extra empty line at the top of the file, away from my Vim cursor. I wanted to delete it… without moving the cursor. It seems like Vim almost lets you do this, with :[range]d. But it leaves the cursor on the deleted line, which isn’t very magical. This is the hack we found: :[range]d Then: '' '' returns the cursor to the last jump point. ...

Today I used Ruby’s Kernel::abort for the first time. It’s one of those incredibly useful methods I can’t believe I’ve never seen before. Observe: # abort.rb {1} def no_message abort end def message abort('Process terminated') end $ irb 2.2.2 :001 > require './abort' => true 2.2.2 :002 > no_message $ irb {1} 2.2.2 :001 > require './abort' => true 2.2.2 :002 > message Process terminated $ Use it to bail from a script. ...

Today I learned that I have thirty-nine Postgres databases on my computer, after running this command inside psql: \l ; Each one is small, but I don’t like to carrying around old data. I ended up dropping nine of them, with: drop database foo_development; For a lighter storage and cognitive load.

This week I learned that attr_reader is more performant than a simple getter method. Here’s a gist from five years ago where Aaron Patterson explains: https://gist.github.com/pjb3/629716 I ran that same benchmarking script today on Ruby 2.2.3. The gap has narrowed, but still exists: ruby-2.2.3 Rehearsal ----------------------------------------------- method 0.070000 0.000000 0.070000 ( 0.074840) attr_reader 0.050000 0.000000 0.050000 ( 0.052603) -------------------------------------- total: 0.120000sec user system total real method 0.070000 0.000000 0.070000 ( 0.072229) attr_reader 0.050000 0.000000 0.050000 ( 0.053374) I like attr_reader because it’s a Ruby convention and is one line instead of three. Now, I also like its performance relative to a getter. ...

I like to read commit logs. Today I wanted to see the first commit on a project. Here’s what I used: git rev-list --max-parents=0 HEAD Show me the commits that led to HEAD in reverse chronological order; then limit that list to the commits with no parent. Here’s a small modification, to show the entire commit rather than the SHA alone: git show $(git rev-list --max-parents=0 HEAD)

Today I found a useful method in ActiveRecord, restore_attributes. This method restores attributes on a dirty model. Use it when you are hacking in the Rails console and want to quickly return to a clean slate. Dirty the record: [1] pry(main)> p = Post.first Post Load (0.4ms) SELECT "posts".* FROM "posts" ORDER BY "posts"."id" ASC LIMIT 1 => #<Post:0x007f8462b09eb8 id: 106, title: "Hello World!", created_at: Sun, 09 Feb 2014 17:15:01 CST -06:00, url_slug: "hello-world"> [2] pry(main)> p.url_slug = 'foobar' => "foobar" [3] pry(main)> p.created_at = Time.now => 2015-10-13 11:41:37 -0500 [4] pry(main)> p => #<Post:0x007f8462b09eb8 id: 106, title: "Hello World!", created_at: Tue, 13 Oct 2015 11:41:37 CDT -05:00, url_slug: "foobar"> And restore: ...

I’m a huge fan of Vim buffers. I try to have my buffer list roughly mirror the files I am currently holding in my brain. The BufExplorer Vim plugin helps, and is included in the Hashrocket Dotmatrix. Today I learned to use the command \bs, which opens a colorful buffer list that you can navigate with Vim directions. https://github.com/jlanzarotta/bufexplorer