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HikaruEgashira/typed-format.ts

Last active July 6, 2023 09:56
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C言語などによくあるprintfにTypeScriptで型をつける
Raw
typed-format.ts
type Parser<T> =
T extends `%s${infer U}`? [string, ...Parser<U>]
: T extends `%d${infer U}` ? [number, ...Parser<U>]
: T extends `${string}${infer U}` ? Parser<U>
: [];
type Format = <T extends string>(str: T, ...params: Parser<T>) => string
const format: Format = (str, ...params) => str // WIP
format("$%d/%s", 5, "day") // $5/day
// ^? const format: <"$%d/%s">(str: "$%d/%s", params_0: number, params_1: string) => string
// playground-> https://www.typescriptlang.org/play?jsx=0&pretty=true#code/PTAEGFAAow8qMOwYAcBOBLAdgFwDasNYMho9UCSGQEwZBFBkGiGAKApFAFIBnAWgD5R70VUBzasWgExahUAVwC2AIwCmiKugCe8KaAAKAQ0T0ZAHgAqrALwVQJ07tBSAHuimp+9UAAMGAEgDeaAGYzQAVQC+jgD8oADa7JxcADSgAHTx6po6vswAusamAFyg5lY2dg7O-O5ePgGOoCGhopIyMfGxiVqI2inppqDZuda29k7uEWhc-iWo3oh+gZWqGs2tzBkm2aGpANwUCkqgAGIA9ohiauigBqB6Fj0FbBxDzAAUEV318fAaamL02U06+gCUJ6xBtwqABjXaodigTz7Q7obJ7A5HE6gB4cZ6xV6Id70f4GQEcUA0ADqAEkVBRoYj0HcAEQuATABg0mIAVhiNP4ankNP+NBcLOAnPkvFAAD0ghQgA
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