method REPLServer.prototype.defineCommand
Usage in Deno
```typescript import { REPLServer } from "node:node__repl.d.ts"; ```
REPLServer.prototype.defineCommand(keyword: string,cmd: REPLCommandAction | REPLCommand,): void
The `replServer.defineCommand()` method is used to add new `.`\-prefixed commands
to the REPL instance. Such commands are invoked by typing a `.` followed by the `keyword`. The `cmd` is either a `Function` or an `Object` with the following
properties:
The following example shows two new commands added to the REPL instance:
```js
import repl from 'node:repl';
const replServer = repl.start({ prompt: '> ' });
replServer.defineCommand('sayhello', {
help: 'Say hello',
action(name) {
this.clearBufferedCommand();
console.log(`Hello, ${name}!`);
this.displayPrompt();
},
});
replServer.defineCommand('saybye', function saybye() {
console.log('Goodbye!');
this.close();
});
```
The new commands can then be used from within the REPL instance:
```console
> .sayhello Node.js User
Hello, Node.js User!
> .saybye
Goodbye!
```
cmd: REPLCommandAction | REPLCommand
The function to invoke when the command is processed.
void