feat: add extension option to support ESM

README.md

@@ -154,7 +154,7 @@ than recursively searching child directories.
 
 ### `-n [name]` or `--name [name]`
 
-Specifies the name to use for creating new barrels (and identifying old ones). `.ts` wil be
+Specifies the name to use for creating new barrels (and identifying old ones). `.ts` will be
 appended if not included in the name. Barrels names will be defaulted to `index.ts`.
 
 ### `-s [mode]` or `--structure [mode]`
@@ -212,6 +212,16 @@ Display the barrelsby version number.
 
 Display additional debug information.
 
+### `-x [extension]`or `--extension [extension]`
+Add extension suffix to exports (e.g. '.js'). Useful for ESM modules.
+
+```TypeScript
+// Without --extension .js
+export * from "./Slider";
+// With --extension .js
+export * from "./Slider.js";
+```
+
 ## Requirements
 
 Requires node v6.0.0 or greater for ES6 syntax.

barrelsby.json

@@ -7,5 +7,6 @@
 	"structure": "filesystem",
 	"verbose": true,
 	"include": [".ts$"],
-	"exclude": ["zeta.ts$"]
+	"exclude": ["zeta.ts$"],
+	"extension": ""
 }

bin/builder.d.ts

@@ -4,9 +4,9 @@ import { SemicolonCharacter } from "./options/noSemicolon";
 import { StructureOption } from "./options/options";
 import { QuoteCharacter } from "./options/quoteCharacter";
 import { Directory, Location } from "./utilities";
-export declare function buildBarrels(destinations: Directory[], quoteCharacter: QuoteCharacter, semicolonCharacter: SemicolonCharacter, barrelName: string, logger: Logger, baseUrl: BaseUrl, exportDefault: boolean, structure: StructureOption | undefined, local: boolean, include: string[], exclude: string[]): void;
-export declare type BarrelBuilder = (directory: Directory, modules: Location[], quoteCharacter: QuoteCharacter, semicolonCharacter: SemicolonCharacter, logger: Logger, baseUrl: BaseUrl, exportDefault: boolean) => string;
+export declare function buildBarrels(destinations: Directory[], quoteCharacter: QuoteCharacter, semicolonCharacter: SemicolonCharacter, barrelName: string, logger: Logger, baseUrl: BaseUrl, exportDefault: boolean, structure: StructureOption | undefined, local: boolean, include: string[], exclude: string[], extension: string): void;
+export declare type BarrelBuilder = (directory: Directory, modules: Location[], quoteCharacter: QuoteCharacter, semicolonCharacter: SemicolonCharacter, logger: Logger, baseUrl: BaseUrl, exportDefault: boolean, extension: string) => string;
 /** Builds the TypeScript */
-export declare function buildImportPath(directory: Directory, target: Location, baseUrl: BaseUrl): string;
+export declare function buildImportPath(directory: Directory, target: Location, baseUrl: BaseUrl, extension: string): string;
 /** Strips the .ts or .tsx file extension from a path and returns the base filename. */
 export declare function getBasename(relativePath: string): string;