FX Asset Classes Typing

fx-asset-classes.ts

type Currency = 'USD' | 'EUR' | 'CZK'
type PreciousMetal = `X${ 'AG' | 'AU' | 'PD' | 'PT' }`
type Treasury = `T${`0${ 2 | 3 | 5 | 7 }` | `${ 1 | 2 | 3 }0`}`

type CurrencyCurrency = `${Currency}${Currency}`
type PreciousMetalCurrency = `${PreciousMetal}${Currency}`
type TreasuryCurrency = `${Treasury}${Currency}`
 
type InstrumentNames = CurrencyCurrency | PreciousMetalCurrency | TreasuryCurrency


type AssetClass<T> = T extends `X${string}`
    ? 'PreciousMetal'
    : T extends `T${'0' | '1' | '2' | '3'}${string}`
        ? 'Treasury'
        : 'FX'

type PM = AssetClass<'XAUUSD'>
type T = AssetClass<'T10USD'>
type FX = AssetClass<'foo'>


type Instruments = {
    [K in InstrumentNames]: AssetClass<K>
}