Tests as docs? 🤔
Tests can serve as documentation. But the default `mix test` command doesn't print them out in a way that has clear information. Thankfully, there are two flags that can make it really nice.
elixir 🏷️
Why were Phoenix Contexts introduced? A (brief) history.
People frequently struggle with Phoenix Contexts. They ask, 'Why were they introduced?' A brief history of why they were introduced might be helpful.
🤨 What do you name your own `link` component in a Phoenix codebase?
What should we name our own “link” component in a Phoenix codebase? We cannot call it <.link> because that comes with Phoenix out of the box. This is what I do.
✨ Elixir 1.17's new Date.shift/2 🕐
Elixir's new `Date.shift/2` is really cool, but you have to keep in that it's not doing arithmetic operations. Check it out.
How to find the 🐢 slowest N modules in test suite
If you want to improve your test suite speed, the first thing we want to do is find out what's the slowest module we have, right? Elixir 1.17's got your back.
🔍 ExUnit 1.17's new flag to find intermittent failures
Intermittent tests are a pain, but Elixir 1.17 has a really cool new flag in `mix test` to help us.
😲 Test breakpoints? New in Elixir 1.17 ✨
Elixir 1.17 shipped with a new feature that lets us put breakpoints right into our tests! All we have to do is run them with --breakpoints. Too good to be true? Check it out!
⚡ How to auto-format functions without parentheses
Have you ever wondered how Phoenix and Ecto have functions whose arguments the Elixir formatter doesn't automatically wrap with parentheses? Let me show you how to get that in your own project!
🤔 How to inject a list into a quoted expression
How can we inject a list into another list in a quoted expression? Turns out, our friend `quote/1` doesn't do the trick. But this other helper does!
⚡ Helpful tip to debug Elixir macros!
When dealing with macros, it's sometimes hard to know what a quoted expression evaluates to. So let me show you this helper
What do Elixir's quote and unquote do (metaprogramming)? 🤔
If you've ever looked at a using macro (or any other macro for that matter), you've probably seen quote and unquote. What do those do? Let me show you.
🔍 Find a dependency's modules and functions
If you ever want to find one of your dependencies' modules and functions programmatically. This tip is for you.
Elixir 1.17's ✨ new `to_timeout/1` helper!
Elixir 1.17 ships with a brand new `to_timeout/1` helper that helps us create timeout durations in a more natural language!
⏱️ Use these `:timer` helpers to remove magic ms numbers
Many functions in Elixir take milliseconds as an argument. Don't leave magical millisecond numbers everywhere. Use these `:timer` helpers instead.
⚡️ Tracing with Recon
It's mind blowing how powerful (and simple) tracing is in Elixir. Here's a quick intro into tracing in Elixir with Recon.
The right way to update Elixir structs (and how not to do it 😁)
I think there is a right way (and a wrong way) to update Elixir structs -- at least that's if you want to know when you accidentally type the wrong thing! Let me show you the differences.
🪄 Elixir's magic word-list sigil
Sometimes it's a pain to write long lists... Have you ever forgotten to remove that last trailing comma? Yeah, me too. 🤦 Thankfully, there's a sigil that lets us type less (and have more power!)
Elixir & Erlang's new process labels! 🔥
Elixir 1.17 and Erlang 27 just added new process labels!
Erlang ❤️ JSON
Erlang 27 just came out, and one of the highlights is the new built-in `:json` module!
😎 A cool use of Elixir's `String.split/2` I didn't know about
Need to split a string that has two delimiters? This is a cool trick.
2 Helpers to Keep Your Pipelines Flowing! 😎
Elixir code tends to be pipe-friendly. But sometimes that fails. You have a pesky break in your pipeline! Here are 2 helpers that can help you keep your pipeline flowing!
🤔 and/or Vs. &&/||. Which to use?
People new to Elixir ask, which should I use? and/or OR &&/||? They're not the same. Here are some useful differences and some pitfalls.
♻️ Refactoring complex `else` clauses in `with` (an anti-pattern)
Elixir's `with` clauses are awesome for organizing happy paths. But sometimes the `else` clauses get really messy and difficult to understand. Let's refactor that.
🔄 Refactoring an anti-pattern: complex extractions in function heads
When we use function-head pattern matching as control flow and as an extraction mechanism, we make it difficult to know what's important in our code and what's merely convenience! Let's refactor it.
🤩 Better defaults with Enum.find/3
Enum.find/2 returns `nil` when a value can't be found. That's not always desirable. Sometimes, it's nicer to provide a better default. Thankfully, that's what Enum.find/3 gives us!
⚙️ Set your preferred CLI env for mix aliases
At some point, you might introduce a new `mix` alias to run a subset of your tests. But that runs in `dev` by default. How can we change the default to `test`?
Debugging tip! One quick way to find out which functions you're executing.
When running tests we sometimes want to know which functions are being executed. But it's a pain to write custom dbg statements. How can we print the name of the function without having to know it?
Introspecting modules at runtime 🔎
Module's functions are for dealing with modules at compile time. What about runtime? We have `Module.__info__/1` just for that!
Elixir 1.16 running multiple tests with line numbers! ✅
Prior to Elixir 1.16 we couldn't run multiple test files with their line numbers. With Elixir 1.16, we can!
Elixir 1.16's Improved Docs 📚
Elixir 1.16.rc just came out, and there are four noteworthy improvements to docs
Dependencies in Scripts with Mix.install
If we want to add packages to our Elixir scripts, Mix.install is the tool to use!
Strong Arrows
Elixir might add types through gradual typing. But that comes with some challenges. Check out Elixir's new way of handling some of those gradual typing challenges with strong arrows.
Elixir Types: Operator Precedence
The Elixir types paper talks about operator precedence. Let's take a look at how that changes how we read type signatures.
Elixir's intersection types
José Valim talked about types in ElixirConf 2023. I read the paper to understand why we need intersection types for some type signatures. Let me break down why!
Creating infinite sequences with Stream.unfold/2
Ever want to create an infinite sequence? Check out how we can do that with `Stream.unfold/2`. We even generate the famous fibonacci sequence.
Turn maps (and keyword lists) into structs
One nice way of turning a map or keyword list into an existing struct is to use `struct/2` or `struct!/2`. Check it out!
Run a function N times
Ever wanted to run a function in Elixir `N` times? I got the thing just for you!
Comparing dates in Elixir
Elixir 1.15 introduced new `DateTime` and `Date` functions to compare dates. Let's cover what's new, what we already had, and what to avoid at all costs!
Elixir's optional syntax
I always knew that Elixir had some optional syntax, but I didn't realize how prevalent it was!
Elixir 1.15 deprecates Logger.warn/2 in favor of Logger.warning/2
Elixir 1.15 is deprecating `Logger.warn/2` in favor of `Logger.warning/2`.
Recompile your code from within IEx
I've seen people quit out of IEx and restart it to load new changes to their code. Here are some cool helpers for you.
Getting previous values in IEx
To access previous values in IEx (and save some typing) use the `v/1` helper.
Build your own lazy operation evaluator
I'm always fascinated by how Elixir's Stream module handles operations lazily by storing them in a struct.
How to check if two lists contain overlapping elements
Want to check if two lists have overlapping elements in Elixir?
Long-lived Processes in Elixir
Tail call (or last call) optimization is the trick to having long-lived processes. Never ceases to amaze!
Prying into Elixir dependencies
I love how easy it is to do code spelunking 🤿 in Elixir projects!
Updating nested structs in Elixir with put_in/2
Updating nested data in Elixir can be tough, since all data is immutable. But there's a `put_in/2` macro that works really nicely with structs!
Prying in Elixir with dbg/2 and iex
People asked me in previous videos, what about dbg/2 with iex? Spoiler alert — also awesome! ⚡️
dbg/2 and IO.inspect/2 `:printable_limit` option to print entire output
TIL about the `:printable_limit` option for `dbg/2` and `IO.inspect/2`.
Goodbye IO.Inspect. Hello dbg
Elixir 1.14 introduced `dbg`, a debugging helper that is much more powerful than `IO.inspect` but equally easy to use!
Elixir 1.14's new :optional option when deriving Inspect protocol
Elixir 1.14 introduced a new option when deriving the Inspect protocol for a struct.
Using mix help to get docs for mix tasks (like Phoenix generators)
I love `mix help` to get the docs for mix tasks right from the command line.
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