fix: update return types

Author: kgryte

lib/node_modules/@stdlib/fs/read-json/docs/types/index.d.ts

@@ -55,9 +55,9 @@ type Reviver = ( key: string, value: any ) => any;
 * Callback invoked upon reading a file.
 *
 * @param err - error object
-* @param file - file contents
+* @param data - file contents
 */
-type Callback = ( err: Error | null, file: Buffer | string ) => void;
+type Callback<T> = ( err: Error | null, data: T ) => void;
 
 /**
 * Interface for reading a file as JSON.
@@ -85,7 +85,7 @@ interface ReadJSON {
 	*     console.dir( data );
 	* }
 	*/
-	( file: string | Buffer | number, options: Options | string, clbk: Callback ): void;
+	<T = unknown>( file: string | Buffer | number, options: Options | string, clbk: Callback<T> ): void;
 
 	/**
 	* Asynchronously reads a file as JSON.
@@ -105,7 +105,7 @@ interface ReadJSON {
 	*     console.dir( data );
 	* }
 	*/
-	( file: string | Buffer | number, clbk: Callback ): void;
+	<T = unknown>( file: string | Buffer | number, clbk: Callback<T> ): void;
 
 	/**
 	* Synchronously reads a file as JSON.
@@ -127,7 +127,7 @@ interface ReadJSON {
 	* }
 	* console.dir( out );
 	*/
-	sync( file: string | Buffer | number, options?: Options | string ): string | Error;
+	sync<T = unknown>( file: string | Buffer | number, options?: Options | string ): T | Error;
 }
 
 /**

lib/node_modules/@stdlib/fs/read-json/docs/types/test.ts

@@ -18,11 +18,17 @@
 
 import readJSON = require( './index' );
 
-const onLoad = ( error: Error | null, file: string | Buffer ) => {
-	if ( error || !file ) {
+/**
+* Callback function.
+*
+* @param error - error object
+* @param data - results
+*/
+function onLoad( error: Error | null, data?: Array<string> | Buffer ): void {
+	if ( error || !data ) {
 		throw error;
 	}
-};
+}
 
 
 // TESTS //
@@ -105,9 +111,9 @@ const onLoad = ( error: Error | null, file: string | Buffer ) => {
 	readJSON( 'C:\\foo\\bar\\baz\\package.json' ); // $ExpectError
 }
 
-// Attached to main export is a `sync` method which returns a string or an error...
+// Attached to main export is a `sync` method which returns results or an error...
 {
-	readJSON.sync( 'package.json' ); // $ExpectType string | Error
+	readJSON.sync<Array<string>>( 'package.json' ); // $ExpectType Error | string[]
 }
 
 // The compiler throws an error if the `sync` method is provided a first argument which is not a string, buffer, or file descriptor...