Messaging
Protocol Maps
Overview
Protocol maps define types for sendMessage and onMessage in a single place. You'll never need to write type parameters; the data and return types will be inferred automatically!
Syntax
Protocol maps are simple interfaces passed into defineExtensionMessaging. They specify a list of valid message types, as well as each message's data type and return type.
interface ProtocolMap {
message1(): void; // No data and no return type
message2(data: string): void; // Only data
message3(): boolean; // Only a return type
message4(data: string): boolean; // Data and return type
}
export const { sendMessage, onMessage } = defineExtensionMessaging<ProtocolMap>();
When calling sendMessage or onMessage, all the types will be inferred:
onMessage('message2', ({ data /* string */ }) /* : void */ => {});
onMessage('message3', (message) /* : boolean */ => true);
const res /* : boolean */ = await sendMessage('message3', undefined);
const res /* : boolean */ = await sendMessage('message4', 'text');
Async Messages
All messages are async. In your protocol map, you don't need to make the return type Promise<T>, T will work just fine.
interface ProtocolMap {
- someMessage(): Promise<string>;
+ someMessage(): string;
}
Multiple Arguments
Protocol map functions should be defined with a single parameter, data. To pass more than one argument, make the data parameter an object instead!
interface ProtocolMap {
- someMessage(arg1: string, arg2: boolean): void;
+ someMessage(data: { arg1: string; arg2: boolean }): void;
}
await sendMessage('someMessage', { arg1: ..., arg2: ... });