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@danfrydevNov 1

TypeScript can check a credit card number's checksum (Luhn). One wrong digit is a compile error, no runtime code.

TypeScript code in an editor. Recursive types reverse a card number's digits, double every second one and add them up, and the number passes if the total ends in 0. A card() function uses the result: three valid card numbers compile, and the same numbers with one digit changed show red squiggles and the error "Argument of type ... is not assignable to parameter of type 'never'".

ALT TypeScript code in an editor. Recursive types reverse a card number's digits, double every second one and add them up, and the number passes if the total ends in 0. A card() function uses the result: three valid card numbers compile, and the same numbers with one digit changed show red squiggles and the error "Argument of type ... is not assignable to parameter of type 'never'".

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@danfrydevOct 30

Replying to @thymikee

Image from Daniel Fry (@danfrydev)

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@danfrydevOct 29

#ggg is now a compile error. TypeScript types can check hex colors, alpha included, no runtime code.

Image from Daniel Fry (@danfrydev)

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@danfrydevOct 26

I built a Spotify client for the terminal. waxon has vim keys, album art and synced lyrics, and it can play music by itself or drive the Spotify app. Free and open source. Try the demo in your browser 👇

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@danfrydevOct 25

Replying to @SunWeatherMan

🤖 Made with AI

Image from Daniel Fry (@danfrydev)

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@danfrydevOct 25

Typo a CSS module class and tsc fails. No codegen, no .d.ts files. typed-css-imports uses content mappers from the TypeScript 7.1 beta, so styles.buttn is an error in your editor and in CI. Completions update as you type in the CSS file. Sass works too. pnpm add -D typed-css-imports [email protected] github.com/danfry1/typed-css…

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@danfrydevOct 21

building on this: port 65536 is now a compile error. no runtime check, no recursion 🧱

TypeScript code defining a Port type that accepts 1 to 65535, digit by digit, using template literal types. listen(3000) and listen(65535) compile, while listen(65536) and listen(0) are underlined in red as errors.

ALT TypeScript code defining a Port type that accepts 1 to 65535, digit by digit, using template literal types. listen(3000) and listen(65535) compile, while listen(65536) and listen(0) are underlined in red as errors.

@danfrydevOct 20

turns out TypeScript types can enforce a min and max string length too

TypeScript code: a Username template literal type built from 3 required one-character placeholders and 5 optional ones, so only strings of 3 to 8 characters are allowed. "dan" and "danfry" compile; "df" (too short) and "danfrydev" (too long) are errors.

ALT TypeScript code: a Username template literal type built from 3 required one-character placeholders and 5 optional ones, so only strings of 3 to 8 characters are allowed. "dan" and "danfry" compile; "df" (too short) and "danfrydev" (too long) are errors.

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@danfrydevOct 20

turns out TypeScript types can enforce a min and max string length too

TypeScript code: a Username template literal type built from 3 required one-character placeholders and 5 optional ones, so only strings of 3 to 8 characters are allowed. "dan" and "danfry" compile; "df" (too short) and "danfrydev" (too long) are errors.

ALT TypeScript code: a Username template literal type built from 3 required one-character placeholders and 5 optional ones, so only strings of 3 to 8 characters are allowed. "dan" and "danfry" compile; "df" (too short) and "danfrydev" (too long) are errors.

@danfrydevSep 27

turns out TypeScript types can enforce an exact string length

Image from Daniel Fry (@danfrydev)

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@danfrydevOct 19

Built an open benchmark off the back of this: 5 typescript checkers, 3 real projects, raw output behind every result Controlled numbers come in under my quick first run. tsc-ts is 4.5x faster than tsgo on type-fest at defaults, 3.4x with both at 10 threads. ts-checker-bench.danfry.dev

@cramforceOct 18

TypeScript is 6 times faster than go[*]

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@danfrydevSep 27

another use: Ethereum addresses vs hashes (the case @MicahZoltu asked for in TypeScript issue #52243). Address = exactly 40 hex chars, Hash = exactly 64, so mixing them up is a compile error. no brands, no runtime code. playground: typescriptlang.org/play/?#co…

Image from Daniel Fry (@danfrydev)

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@danfrydevSep 27

turns out TypeScript types can enforce an exact string length

Image from Daniel Fry (@danfrydev)

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@danfrydevJun 13

love this effect in @opencode

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@danfrydevApr 2

Built a vim-modal Spotify TUI in Go. Album art rendered with Unicode half-blocks, full vim keybindings, command mode. Powered by @charmcli

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@danfrydevMar 7

Replying to @adocomplete

🚀

Image from Daniel Fry (@danfrydev)

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@danfrydev11 Sep 2022

Had a great time at #SvelteSummit and met some really amazing people, was also fortunate to get the chance to meet some of the folks who have had a major influence in my coding journey thus far - @Rich_Harris && @swyx - the future of webdev is looking bright! – at Stockholm, Sweden

Image from Daniel Fry (@danfrydev)

Image from Daniel Fry (@danfrydev)

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