TypeScript – How can omit some items from an Enum in TypeScript?

As of TypeScript 2.8 and the addition of conditional types, you can use the built-in Exclude to exclude certain enum values:

const enum Errcode {
    Ok=0,
    Error=1,
    AccessDeny=201,
    PostsNotFound=202,
    TagNotFound=203,
    //...
}

type SuccessErrcode = Errcode.Ok;
type NotFoundError = Errcode.PostsNotFound|Errcode.TagNotFound;
type ErrorErrcode = Exclude<Errcode, Errcode.Ok>;

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