webextension-rpc/example

import { remoteFunction, makeRemotelyCallable } from 'webextension-rpc';
import type { RpcInfo } from 'webextension-rpc';
// Only import the *types* of the remote script’s functions.
import type { contentScriptRemoteFunctions } from './content-script';

// From background to content script.
const setColour = remoteFunction<typeof contentScriptRemoteFunctions.setColour>(
  'setColour',
  { tabId: 123 },
);
await setColour('blue');

// From content to background script.
export const backgroundScriptRemoteFunctions = makeRemotelyCallable({
  async duplicateTab(rpcInfo: RpcInfo, active: boolean) {
    const newTab = await browser.tabs.duplicate(rpcInfo.tab.id, { active });
    return newTab.id;
  },
});