TTC
Theo's Typesafe Cult•2y ago
Luc Ledo

How to extract tuple from array of objects for Zod enums?

export const PLANS = [
  {
    id: "0",
    name: "free",
    price: 0,
    description: "Free Video Stream",
  },
  {
    id: "price_1Nd",
    name: "basic",
    price: 5,
    description: "Basic Video Stream",
  },
  {
    id: "price_1Nd",
    name: "standard",
    price: 10,
    description: "Standard Video Stream",
  },
  {
    id: "price_1Nd",
    name: "premium",
    price: 20,
    description: "Premium Video Stream",
  },
] as const

const planNames = PLANS.map((plan) => plan.name)
// ("free" | "basic" | "standard" | "premium")[] what I get
// ["free", "basic", "standard", "premium"] what I want
export const PLANS = [
  {
    id: "0",
    name: "free",
    price: 0,
    description: "Free Video Stream",
  },
  {
    id: "price_1Nd",
    name: "basic",
    price: 5,
    description: "Basic Video Stream",
  },
  {
    id: "price_1Nd",
    name: "standard",
    price: 10,
    description: "Standard Video Stream",
  },
  {
    id: "price_1Nd",
    name: "premium",
    price: 20,
    description: "Premium Video Stream",
  },
] as const

const planNames = PLANS.map((plan) => plan.name)
// ("free" | "basic" | "standard" | "premium")[] what I get
// ["free", "basic", "standard", "premium"] what I want
I need this for zod validation. Currently, I'm doing this way. 
  z.object({
    stripeProductId: z.string(),
    planName: z.enum(["free", "basic", "standard", "premium"]),
  }),
  z.object({
    stripeProductId: z.string(),
    planName: z.enum(["free", "basic", "standard", "premium"]),
  }),
2 Replies
Max
Max•15mo ago
@Apestein type: z.nativeEnum(YourPrismaEnum),
Luc Ledo
Luc LedoOP•15mo ago
Don't think you understood the question. Here is the answer I found though in case anyone else needs it. 
const tupleMap = <
  const T extends readonly Record<string, unknown>[],
  Key extends keyof T[number],
>(
  input: T,
  key: Key,
): { [k in keyof T]: T[k][Key] } => {
  return input.map((row) => row[key as never]) as never
}
export const planTuple = tupleMap(PLANS, "name") //type will be: const planTuple: readonly ["free", "basic", "standard", "premium"]
const tupleMap = <
  const T extends readonly Record<string, unknown>[],
  Key extends keyof T[number],
>(
  input: T,
  key: Key,
): { [k in keyof T]: T[k][Key] } => {
  return input.map((row) => row[key as never]) as never
}
export const planTuple = tupleMap(PLANS, "name") //type will be: const planTuple: readonly ["free", "basic", "standard", "premium"]

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