react-vite-demo

objects.ts

(1705B)

 type KeysOfType<T, U> = {
     [K in keyof T]: T[K] extends U ? K : never
 }[keyof T]
 
 type NumberKeysOf<T> = KeysOfType<T, number>
 
 export const SORT_TYPES = ["ascending", "descending"] as const
 export type SortType = typeof SORT_TYPES[number]
 
 export function isSortType(value: string | undefined | null): value is SortType {
     return value === "ascending" || value === "descending"
 }
 
 export function asArray<T>(value: T | T[] | undefined | null): T[] {
     return Array.isArray(value) ? value : 
         value !== undefined && value !== null ? [value] : []
 }
 
 export function filterByProp<T extends object>(prop: keyof T, value: T[keyof T], objects: T[]): T[] {
     return objects.filter(object => object[prop] === value)
 }
 
 export function sortByProp<T,>(prop: NumberKeysOf<T>, order: SortType, objects: T[]): T[] {
     return [...objects].sort((a: T, b: T) => {
         if (!order || typeof a[prop] !== "number" || typeof b[prop] !== "number") return 0
         if (order === "ascending") return a[prop] - b[prop]
         return b[prop] - a[prop]
     })
 }
 
 export function minByProp<T extends object>(prop: NumberKeysOf<T>, objects: T[]): T | null {
     if (objects.length === 0) return null
     if (objects.length === 1) return objects[0]
 
     const [fst, snd, ...tail] = objects
     const min = fst[prop] < snd[prop] ? fst : snd
     return minByProp(prop, [min, ...tail])
 }
 
 // Alternative implementation using reduce
 // const minByProp = <T extends object>(prop: NumberKeysOf<T>, objects: T[]): T | undefined => {
 //   if (objects.length === 0) return undefined
 
 //   return objects.reduce((minObj, currentObj) => {
 //     return currentObj[prop] < minObj[prop] ? currentObj : minObj
 //   })
 // }