feat: consistently export same type for all entrypoints

Defines a `TabFunction` that all entrypoints export, such that we
consistently support the same call signature.

Author: 43081j

src/cac.ts

@@ -4,7 +4,7 @@ import * as fish from './fish';
 import * as powershell from './powershell';
 import type { CAC } from 'cac';
 import { Completion } from './index';
-import { CompletionConfig, noopHandler } from './shared';
+import { noopHandler, TabFunction } from './shared';
 
 const execPath = process.execPath;
 const processArgs = process.argv.slice(1);
@@ -18,10 +18,7 @@ function quoteIfNeeded(path: string): string {
   return path.includes(' ') ? `'${path}'` : path;
 }
 
-export default async function tab(
-  instance: CAC,
-  completionConfig?: CompletionConfig
-) {
+const tab: TabFunction<CAC> = async (instance, completionConfig) => {
   const completion = new Completion();
 
   // Add all commands and their options
@@ -104,3 +101,5 @@ export default async function tab(
 
   return completion;
 }
+
+export default tab;

src/citty.ts

@@ -11,7 +11,7 @@ import type {
   SubCommandsDef,
 } from 'citty';
 import { generateFigSpec } from './fig';
-import { CompletionConfig, noopHandler } from './shared';
+import { CompletionConfig, noopHandler, TabFunction } from './shared';
 
 function quoteIfNeeded(path: string) {
   return path.includes(' ') ? `'${path}'` : path;
@@ -92,10 +92,7 @@ async function handleSubCommands(
   }
 }
 
-export default async function tab<TArgs extends ArgsDef>(
-  instance: CommandDef<TArgs>,
-  completionConfig?: CompletionConfig
-) {
+const tab: TabFunction<CommandDef<ArgsDef>> = async (instance, completionConfig) => {
   const completion = new Completion();
 
   const meta = await resolve(instance.meta);
@@ -206,6 +203,8 @@ export default async function tab<TArgs extends ArgsDef>(
   return completion;
 }
 
+export default tab;
+
 type Resolvable<T> = T | Promise<T> | (() => T) | (() => Promise<T>);
 
 async function resolve<T>(resolvable: Resolvable<T>): Promise<T> {

src/shared.ts

@@ -1,4 +1,4 @@
-import { Handler } from './index';
+import { Handler, Completion } from './index';
 
 export const noopHandler: Handler = () => {
   return [];
@@ -16,3 +16,8 @@ export interface CompletionConfig {
     }
   >;
 }
+
+export type TabFunction<T> = (
+  instance: T,
+  completionConfig?: CompletionConfig
+) => Promise<Completion>;