CODEWITHSUNDEEP
typescript
li jie
li jie

Reputation: 1

typescript interface field to be const

there is my code

interface page {
  type: '1' | '2'
}

interface Menu {
  id: string,
  title: string,
  page: page,
}

export const menus: Menu[] = [
  {
    id: 'externalCustomer',
    title: 'title',
    page: { type: '1' }
  }
]

is there any way to make id be const? the menus type is Menu[], and menu id is the const, just like

interface page {
  type: '1' | '2'
}

interface Menu<T> {
  id: T[number].id,
  title: string,
  page: page,
}

export const menus: Menu<typeof menus>[] = [
  {
    id: 'externalCustomer',
    title: 'title',
    page: { type: '1' }
  }
]

i try to write it like

const menus = [
  {
    id: 'externalCustomer',
    title: 'title',
    page: { type: '1' }
  }
] as const

but in this way, the type of page will be lose

Upvotes: 0

Views: 134

Answers (1)

Lee Jeonghyun
Lee Jeonghyun

Reputation: 150

Using union type might does the job.

interface page {
  type: '1' | '2'
}

interface Menu<I> {
  id: I,
  title: string,
  page: page,
}

const menus: Menu<'externalCustomer' | 'test'>[] = [
  {
    id: 'externalCustomer',
    title: 'title',
    page: { type: '1' }
  }, {
    id: 'test',
    title: 'title',
    page: { type: '1' }
  }, {
    id: 'aaa', //type error
    title: 'title',
    page: { type: '1' }
  },
];

Upvotes: 1

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