How to describe the type of a dictionary in typescript efficiently?-CodePudding

How to describe the type of a dictionary in typescript more efficient, than the solution below?

type DictEntry = { [key: string]: string }
type UploadDict = { [key: string]: DictEntry }

const UPLOAD_TYPE_DICT: UploadDict = {
  JPG: {
    label: "jpg",
    type: "image/jpeg",
  },
  PNG: {
    label: "png",
    type: "image/png",
  },
}

CodePudding user response：

I can see some type patterns from your example, so I'd propose using enum to keep file types and using DictEntry to keep label and type as strongly-typed properties

You can check the playground here

enum FileType {
  JPG,
  PNG
}

type DictEntry = { label: string, type: string }
type UploadDict = { [K in keyof typeof FileType]: DictEntry }

const UPLOAD_TYPE_DICT: UploadDict = {
  JPG: {
    label: "jpg",
    type: "image/jpeg",
  },
  PNG: {
    label: "png",
    type: "image/png",
  },
}

CodePudding user response：

If you mean a cleaner syntax with more efficiently use Record.

type DictEntry = Record<string, string>
type UploadDict = Record<string, DictEntry>

const UPLOAD_TYPE_DICT: UploadDict = {
  JPG: {
    label: "jpg",
    type: "image/jpeg",
  },
  PNG: {
    label: "png",
    type: "image/png",
  },
}