Dynamic property names in flow typed object

Question

I'm slowly and surely working flowType into my code, but I'm struggling with one concept.

How do I specify the type of unknown, dynamically named properties of an object?

For example my user object might have an object containing organisations with unique keys.

How would I define this?

export type User = ?{   currentOrg: string,   displayName?: string,   email: string,   emailVerified: boolean,   newAccount: boolean,   organisations?: {      UNKNOWNKEY?: string {        orgData1: string,        orgData2: string,      }   },   uid: string,   photoUrl?: string, }; 

Would really appreciate any help on this. Thanks!

Answer 1

Flow has specific syntax for objects that behave like maps:

{ [key: K]: V } 

where K is they type of the keys and V is the type of the values.

Your full example would look like:

export type User = {   currentOrg: string,   displayName?: string,   email: string,   emailVerified: boolean,   newAccount: boolean,   organisations?: { [key: string]: string },   uid: string,   photoUrl?: string, };