CODEWITHSUNDEEP
typescript
geek machine
geek machine

Reputation: 173

How to traversal an enum?

Type 'string' cannot be assigned to type 'online' | 'offline'. I should be missing something，But I don't know how to do. 

enum StatusOptions {
  ONLINE = 'ONLINE',
  OFFLINE = 'OFFLINE',
}
Object.keys(StatusOptions).map((item: keyof typeof StatusOptions) => {
    return {
      text: StatusOptions[key],
      value: item
    }
})

Upvotes: 0

Views: 50

Answers (1)

r3dst0rm
r3dst0rm

Reputation: 1926

Type 'string' cannot be assigned to type 'online' | 'offline' results from a mistyped function parameter, which you pass into your map function.

Object.keys is defined as:

    /**
     * Returns the names of the enumerable string properties and methods of an object.
     * @param o Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.
     */
    keys(o: object): string[];

Therefore you have to correctly type your function. Where item, is a string

Object.keys(StatusOptions).map((item: string) => /* do something with it */);

Just in case you want then use the item as a key for StatusOptions like: StatusOptions[item]. You have to cast it as the following:

Object.keys(StatusOptions).map((item: string) => {
    return {
      text: StatusOptions[item as keyof typeof StatusOptions],
      value: item
    }
})

Upvotes: 1

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