Obj (Object)

Property access (dual)

pick<T, K extends keyof T>(obj: T, keys: K[]): Pick<T, K>
omit<T, K extends keyof T>(obj: T, keys: K[]): Omit<T, K>
path<T, P extends string>(obj: T, path: P): PathValue<T, P> | undefined
pathOr<T, P extends string, D>(obj: T, path: P, defaultValue: D): PathValue<T, P> | D

Property mutation (dual, immutable)

assoc<T, V>(obj: T, key: string, value: V): T & Record<string, V>
dissoc<T>(obj: T, key: string): Partial<T>
evolve<T>(obj: T, transformations: Partial<{ [K in keyof T]: (v: T[K]) => T[K] }>): T

Merging (dual)

mergeDeepLeft<T>(a: T, b: T): T
mergeDeepRight<T>(a: T, b: T): T
mergeWith<T, V>(a: T, b: T, resolver: (l: V, r: V) => V): T

Examples

import { pipe, Obj } from '@stopcock/fp'

// strip sensitive fields before sending to client
const safe = pipe(user, Obj.omit(['password', 'ssn']))

// extract fields for a form
const formData = pipe(user, Obj.pick(['name', 'email', 'phone']))

// safe nested access
pipe(order, Obj.pathOr('shipping.address.zip', 'N/A'))

// immutable update
pipe(user, Obj.assoc('role', 'admin'))

// transform multiple fields at once
pipe(
  config,
  Obj.evolve({
    port: (p: number) => p + 1,
    host: (h: string) => h.toLowerCase(),
  }),
)

// deep merge with priority
const merged = Obj.mergeDeepRight(defaults, userPrefs)