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techsavvytravvy.com
trav
@techsavvytravvy.com
4.5K followers 830 following 1.4K posts
sr software engineer @ crunchyroll
🦀🔪 @ crablang
winning the fight against Big Outside™
2024 hellthread heavyweight champion

gas station snack enthusiast, father of some, does leetcode problems hardest to easiest, never sleeps, sometimes streams
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techsavvytravvy.com
lol it's always this
Screenshot of a post from Elon Musk (@elonmusk) on X (formerly Twitter) stating: 'There was (still is) a massive cyberattack against X. We get attacked every day, but this was done with a lot of resources. Either a large, coordinated group and/or a country is involved. Tracing ...' The profile picture is a cosmic-style black hole, and the verified checkmark is present next to the X logo.
March 10, 2025 at 5:53 PM
techsavvytravvy.com
started reading this to my 4yo tonight and she's about it
Cover of 'The Manga Guide to Databases' by Mana Takahashi and Shoko Azuma. The cover features an anime-style illustration of a fairy character in a green outfit holding a wand, with a magical glow effect. Behind her, three girls in princess attire are standing near a large open book containing database tables and SQL queries. A white castle is visible in the background.
February 22, 2025 at 3:38 AM
techsavvytravvy.com
💜
High quality meme featuring multiple images of Scorpion from Mortal Kombat in his signature yellow ninja outfit with black mask. The character is shown in different art styles and poses against fiery backgrounds. The images are placed around the letters, similar to how Homer decorated his workplace sign that originally read 'DON'T FORGET: YOU'RE HERE FOREVER' with Maggie's photos in The Simpsons. Text reads 'GET: HERE OVER' with the letter 'O' positioned separately, likely referencing Scorpion's famous 'Get Over Here' catchphrase. The image is framed with black corner dots on a very light pink background.
February 21, 2025 at 4:32 AM
techsavvytravvy.com
no the function would return true, causing it to incorrectly be of type 'number' after narrowing with if statement
TypeScript code showing a function isNumber that incorrectly determines if a value is a number by checking if typeof x is 'string'. The function main demonstrates the problem by assigning an unknown type to x and using isNumber in a conditional check. This leads to a faulty type narrowing where x is mistakenly assumed to be a number, causing an error when passed to the square function.
February 1, 2025 at 1:48 AM
techsavvytravvy.com
no because it is narrowing it down to the type and only the specified type or the FAIL unique symbol can be returned, otherwise you'll get an error

you could of course return some literal value matching the type but that would have to be pretty deliberate
ts code showing that only the right type can be returned
February 1, 2025 at 1:11 AM
techsavvytravvy.com
don't even need the deepEquals since the type will be narrowed by returning the FAIL symbol. so if it's not that, it should be our type
TypeScript code defining a generic function createPredicate<T> that enforces an explicit type parameter using a TS error. It uses NoInfer<T> and an alternative failure type S, which extends symbol and is assigned typeof FAIL. The function returns a predicate that checks whether applying f(x) does not return FAIL. Below, a specific predicate isString is created using createPredicate<string>, verifying if a value is a string.
January 31, 2025 at 11:42 PM
techsavvytravvy.com
i will say, there are some downsides. deepEqual can obviously get expensive if you're comparing a lot of big objects, and there are some dumb things about narrowing that mean you can't return the input directly
TypeScript code defining a type predicate function isUser using createPredicate<User>. The function checks if an input x is an object, not null, has 'name' and 'age' properties, and that 'name' is a string while 'age' is a number. A comment notes that returning x directly is not allowed because its inferred type is object & Record<'name', unknown> & Record<'age', unknown>. However, explicitly returning an object with name and age properties works.
January 31, 2025 at 11:09 PM
techsavvytravvy.com
the initial attempt is fine, but throwing then doing try/catch for each check isn't ideal and the predicate will be inferred for whatever type you return.

instead i want the type param to be used explicitly and we'll return a symbol to indicate failure instead of throwing

i think it's pretty nice!
TypeScript code defining a generic function createPredicate<T> that enforces explicit type parameters and includes a fallback failure symbol (S extends symbol = typeof FAIL). The function takes a predicate function f and returns a type predicate function. If the predicate returns FAIL, it returns false; otherwise, it checks deep equality. Below, an example use case defines isString, which ensures a value is a string, returning FAIL if not.
January 31, 2025 at 10:59 PM
techsavvytravvy.com
so today @shreyascodes.tech had the idea to create an abstraction for predicate functions, and this is what i came up with initially. it works
TypeScript code defining a generic function createPredicate<T> that takes a function f and returns a type predicate function. The function uses deepEquals to verify type correctness inside a try-catch block. Below, an example use case defines isString, a type predicate created using createPredicate<string>, which throws an error if the input is not a string.
January 31, 2025 at 10:59 PM
techsavvytravvy.com
so one of things you can do in typescript is create type predicates that allow you to check if an input value is a specific type with return type `x is Foo`. unfortunately there is nothing that helps you make sure the predicate is accurate - as long as it returns a boolean it will pass
TypeScript code defining two type guard functions: isString and isNumber. The isString function correctly checks if x is a string using typeof x === 'string'. However, the isNumber function mistakenly also checks typeof x === 'string', despite its type guard claiming x is a number. A comment next to the mistake reads '// whoops'.
January 31, 2025 at 10:59 PM
techsavvytravvy.com
can see it better here
January 31, 2025 at 2:36 AM
techsavvytravvy.com
lissajous.ts
January 31, 2025 at 2:09 AM
techsavvytravvy.com
truly

github.com/Gankra/cargo...
Terminal output showing an error message from attempting to run 'cargo mommy check' on 'bappy-script v0.1.3'. The Rust compiler reports a syntax error at 'src/main.rs:20:6', indicating 'expected one of '!' or '::''. The line in question reads 'mods passes;', with an error underline under 'passes'. The output ends with 'error: could not compile 'bappy-script'' followed by a whimsical message: 'mommy knows her little girl can do b'.
January 30, 2025 at 5:53 AM
techsavvytravvy.com
really? i find that usually when it comes to i/o and async ops that my python requires more ceremony and is harder to follow than the equivalent js
Side-by-side comparison of JavaScript and Python asynchronous file processing. The JavaScript example uses 'Promise.all' to concurrently process an array of filenames with 'processFile', handling errors with a catch block. The Python example uses 'asyncio.create_task' to create concurrent tasks for processing files and collects results as tasks complete using 'asyncio.as_completed', handling exceptions with a try-except block.
January 29, 2025 at 9:06 PM
techsavvytravvy.com
oh it's nothing special just a wrapper around the defaults. can be overridden
C code defining a custom memory allocator using function pointers. The code includes an 'Allocator' struct with function pointers for allocation, deallocation, and reallocation. A function 'create_allocator' returns an instance of 'Allocator'. A wrapper function 'realloc_wrapper' is defined, and a global allocator 'GLOBAL_ALLOCATOR' is initialized with 'malloc', 'free', and 'realloc_wrapper' as its function pointers. Header guards ensure the code is included only once.
January 29, 2025 at 7:27 AM
techsavvytravvy.com
ehhh not really, just that a function is dynamically passed to the parent as an argument
code snippet demonstrating higher order functions in typescript
January 29, 2025 at 4:45 AM
techsavvytravvy.com
c code recreating rust's stdlib Vec
January 29, 2025 at 4:25 AM
techsavvytravvy.com
really like this pattern where the type name is also the namespace name bc i don't have to do something like Result.Result that i see some others do with the `import * as Result` thing

tree-shaking could be a concern tho idk
TypeScript code defining a 'Result' type that can be either 'Ok<T>' or 'Err<E>', where 'E' extends 'Error'. A namespace 'Result' contains two functions: 'isOk' checks if a given 'Result' is not an 'Error', and 'isErr' checks if a given 'Result' is an 'Error'. The code demonstrates that a type and a namespace can share the same name.
January 29, 2025 at 4:08 AM
techsavvytravvy.com
crazy i was just looking for this right when you posted
Screenshot of Google Suggestions with a dark theme. The search term is 'gleam,' followed by related suggestions: 'gleam higher kinded types' searched 24 seconds ago, 'gleam roadmap' searched 7 hours ago, 'gleam polymorphism' searched 8 hours ago, and 'gleam custom types' searched 8 hours ago.
December 7, 2024 at 1:02 AM
techsavvytravvy.com
I KNEW IT

more Big Outside™ propaganda
A screenshot of a Bluesky post by 'Allison @adjectiveallison.com' with the text: 'I heard trav is a WILD partier. BIG parties.' The post timestamp reads 'November 30, 2024, at 11:18 AM.' Overlaid annotations circle 'WILD' and 'BIG' in red with added text. Next to 'WILD,' the annotation reads 'wild = OUTSIDE???' in bold red text. Next to 'BIG,' the annotation reads 'BIG!!' also in bold red text.
November 30, 2024 at 4:26 PM
techsavvytravvy.com
oh i guess we're doing winter now
A weather update screenshot. At the top, a 'Winter Weather Advisory' box from the National Weather Service states: 'Winter Weather Advisory. These conditions are expected to last until 7:00 AM, Saturday, November 30.' Below, a section titled 'Flurries Forecasted' says: 'Flurries for the next hour.' A bar graph illustrates flurry intensity increasing over the next hour. The 'Hourly Forecast' below shows: Now - 28°F with snow; 3 PM - 28°F with 100% chance of snow; 4 PM - 27°F with 25% chance of snow; 5 PM - 26°F with cloudy skies; 5:11 PM - Sunset; 6 PM - 25°F, partly cloudy.
November 29, 2024 at 7:15 PM
techsavvytravvy.com
A frog sitting on a plate of baked beans in outer space. Fire is seen at the bottom with embers floating upward The image appears to have been purposefully degraded and distorted. Text overlaid in a whimsical font reads "it is wednesday my dudes".
November 27, 2024 at 3:40 PM
techsavvytravvy.com
oh no
November 27, 2024 at 3:18 PM
techsavvytravvy.com
i always forget you can scope types in typescript just like you can scope variables
Screenshot of TypeScript code demonstrating scoped types and interfaces. The global scope declares 'type X = "q";' and 'interface Y { a: 9 }'. Within a block, a local 'type X = 5;' and 'interface Y { b: 10 }' are declared. In this block: - 'const x: X = 5;' correctly uses the locally scoped type 'X'. - 'const y: Y = { b: 10 };' correctly uses the locally scoped interface 'Y'. Outside the block: - 'const x: X = 5;' causes a type error because it refers to the global type 'X', which expects a string value. - 'const y: Y = { b: 10 };' causes a type error because it refers to the global interface 'Y', which does not have the property 'b'.
November 26, 2024 at 6:44 PM
techsavvytravvy.com
it's gonna be fine
An animated character with a bald head and dark gray skin stands against a background of roaring orange flames. The character is dressed in a white collared shirt with a loosened dark blue tie, their face tilted upward with closed eyes and a tired, yet serene expression. A dark gray background with the word 'burnout' in lowercase, white, sans-serif font centered in the image.
November 26, 2024 at 2:38 PM