Can you explain the significance of the | symbol appearing at the beginning of a data type declaration in TypeScript?

interface MyInterface {     
    someConst:
    | {
        fullName: string
        email: string
      }
    | null
    | undefined
}

I noticed that my linter, tslint, included the initial | in this code snippet.

While I understand that the second and third | represent a union type, I am unsure about the purpose of the first | in this interface. Can someone please explain?

Answer №1

Tslint is designed to improve the readability of code by making it prettier. Although it may seem insignificant, it's important to note that this feature has no impact on the code type and can be disregarded if needed. If given access to the tslint rule settings, I could potentially offer assistance in customizing them to better suit your needs.

Answer №2

There is no obligation to do this action as it does not have any impact. If you share your tslint with me, I can review it and attempt to locate the specific rule.

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