refactored internals for reusability

this will be used for upcoming virtual bundles

lib/bundle/basic.js

@@ -0,0 +1,29 @@
+"use strict";
+
+let generateBundle = require("./bundler");
+let generateConfig = require("./config");
+let { generateError } = require("../util");
+
+let DEFAULTS = {
+	format: "iife"
+};
+
+module.exports = class BasicBundle {
+	constructor(config, { browsers, plugins }) {
+		config = Object.assign({}, DEFAULTS, config);
+		this._config = generateConfig(config, { browsers });
+	}
+
+	compile(entryPoint) {
+		return generateBundle(entryPoint, this._config, this._cache).
+			then(({ code, modules, cache }) => {
+				this._modules = modules; // XXX: only required for non-basic bundles
+				this._cache = cache;
+				return { code };
+			}, err => ({
+				// also report error from within bundle, to avoid it being overlooked
+				code: generateError(err),
+				error: err
+			}));
+	}
+};

lib/bundle/config.js

@@ -54,8 +54,8 @@ function generateConfig({ extensions = [], // eslint-disable-next-line indent
 		esnext, jsx, typescript, // eslint-disable-next-line indent
 		sourcemap, compact }, { browsers }) {
 	let cfg = { sourcemap };
-
 	let plugins = [];
+
 	if(esnext || jsx) {
 		let transpiler = Object.assign({}, esnext, jsx);
 		if(esnext) {

lib/bundle/index.js

@@ -1,24 +1,22 @@
 "use strict";
 
-let generateBundle = require("./bundler");
-let generateConfig = require("./config");
-let { generateError } = require("../util");
+let BasicBundle = require("./basic");
 
-let DEFAULTS = {
-	format: "iife"
-};
-
-module.exports = class Bundle {
+module.exports = class Bundle extends BasicBundle {
 	constructor(entryPoint, target, config, { browsers }) {
-		this.entryPoint = entryPoint;
-		this.target = target;
-
-		config = Object.assign({}, DEFAULTS, config);
+		// extract bundle-specific fingerprinting, if any
+		config = Object.assign({}, config);
 		if(config.fingerprint !== undefined) {
-			this.fingerprint = config.fingerprint;
+			var fingerprint = config.fingerprint; // eslint-disable-line no-var
 			delete config.fingerprint;
 		}
-		this._config = generateConfig(config, { browsers });
+		super(config, { browsers });
+
+		this.entryPoint = entryPoint;
+		this.target = target;
+		if(fingerprint !== undefined) {
+			this.fingerprint = fingerprint;
+		}
 	}
 
 	// compiles the bundle - if a list of file paths is provided, compilation
@@ -32,15 +30,6 @@ module.exports = class Bundle {
 			return false;
 		}
 
-		return generateBundle(this.entryPoint, this._config, this._cache).
-			then(({ code, modules, cache }) => {
-				this._modules = modules;
-				this._cache = cache;
-				return { code };
-			}, err => ({
-				// also report error from within bundle, to avoid it being overlooked
-				code: generateError(err),
-				error: err
-			}));
+		return super.compile(this.entryPoint);
 	}
 };