Adding Denops API to the Plugin

In the previous section, we created a minimal Denops plugin. In this section, we will enhance the plugin by adding an API.

Open denops/denops-helloworld/main.ts and rewrite the content with the following code:

import type { Entrypoint } from "jsr:@denops/std@^7.0.0";
import { assert, is } from "jsr:@core/unknownutil@^4.3.0";

export const main: Entrypoint = (denops) => {
  denops.dispatcher = {
    hello(name) {
      assert(name, is.String);
      return `Hello, ${name || "Denops"}!`;
    },
  };
};

The above code adds a new API hello to the plugin. The hello API takes a string name and returns a greeting message. See About User-Defined APIs in Explanation of the Getting started for details about User-Defined APIs.

note

While Vim script does not facilitate types, Denops uses unknown types on the interface between Vim and Denops. That's why we use unknownutil to ensure that the name is of type string in the above code.

Once you've updated the file, restart Vim, and execute the following command, you will see the message "Hello, Your name!".

:echo denops#request("denops-helloworld", "hello", ["Your name"])

As shown, users can call the Denops API via the denops#request() function.

Denops Documentation

Adding Denops API to the Plugin