Generic with Narrow/Morph

I want to make something like

type UniqueArray<T, K extends keyof T>


export const UniqueArray = brandsScope.type.generic('T', 'K extends keyof T', ['T[]', ':', (v, ctx) => {
  let vals = new Set(v.map(e => e[erm what]))
  if (vals.length !== v.length) return ctx.mustBe(`array with uniue $K`)
  return true
}])

type UniqueArray<T, K extends keyof T>


export const UniqueArray = brandsScope.type.generic('T', 'K extends keyof T', ['T[]', ':', (v, ctx) => {
  let vals = new Set(v.map(e => e[erm what]))
  if (vals.length !== v.length) return ctx.mustBe(`array with uniue $K`)
  return true
}])

Please help me to make it work

2 Replies

Dimava•4d ago

export const UniqueArray = function <const def, const key extends keyof Type<type.infer<def>>['infer'] & string>(
  def: type.validate<def, brandsScope['t']>, key: key,
) {
  return type([
    [def as { key: 'string' }, '[]'], ':', (v, ctx) => {
      const set = new Set(v.map(e => e[key as 'key']))
      if (set.size !== v.length)
        ctx.mustBe(`with unique values of ${JSON.stringify(key)}`)
      return true
    },
  ])
}

export const UniqueArray = function <const def, const key extends keyof Type<type.infer<def>>['infer'] & string>(
  def: type.validate<def, brandsScope['t']>, key: key,
) {
  return type([
    [def as { key: 'string' }, '[]'], ':', (v, ctx) => {
      const set = new Set(v.map(e => e[key as 'key']))
      if (set.size !== v.length)
        ctx.mustBe(`with unique values of ${JSON.stringify(key)}`)
      return true
    },
  ])
}

this does work but I want to see how generics work

ssalbdivad•4d ago

This isn't supported yet https://github.com/arktypeio/arktype/issues/1053 I don't really understand how K is relevant for a unique array anyways

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Generic with Narrow/Morph