added debug mode emitting underlying configuration

this might be useful for debugging, but also for recreating the
corresponding configuration elsewhere (e.g. independent test cases,
migrating away from faucet etc.)

Author: FND

lib/bundle/babel.js

@@ -1,5 +1,6 @@
 "use strict";
 
+let { debug } = require("../util");
 let { loadExtension } = require("faucet-pipeline-core/lib/util");
 
 module.exports = function generateTranspiler({ esnext, jsx, exclude }, { browsers }) {
@@ -33,15 +34,19 @@ module.exports = function generateTranspiler({ esnext, jsx, exclude }, { browser
 		extensions.push(".jsx");
 		let { pragma } = jsx;
 		let options = pragma ? { pragma } : {};
-		plugins.push(["@babel/plugin-transform-react-jsx", options]);
+		let plugin = ["@babel/plugin-transform-react-jsx", options];
+		debug("transpiler plugin:", ...plugin);
+		plugins.push(plugin);
 	}
 
 	if(plugins.length) {
 		settings.plugins = plugins;
 	}
 
-	let babel = loadExtension("rollup-plugin-babel",
-			"failed to activate ESNext transpiler", "faucet-pipeline-esnext");
+	let plugin = "rollup-plugin-babel";
+	debug("plugin:", plugin, settings);
+	let babel = loadExtension(plugin, "failed to activate ESNext transpiler",
+			"faucet-pipeline-esnext");
 	return {
 		plugin: babel(settings),
 		extensions

lib/bundle/bundler.js

@@ -1,3 +1,4 @@
+let { debug } = require("../util");
 let rollup = require("rollup");
 
 let SMPREFIX = "//# sourceMappingURL=";
@@ -8,6 +9,8 @@ module.exports = function generateBundle(entryPoint, config, cache) {
 		input: entryPoint,
 		cache
 	});
+
+	debug("Rollup configuration:", options, writeConfig);
 	return rollup.rollup(options).
 		then(bundle => {
 			cache = bundle;

lib/bundle/config.js

@@ -2,9 +2,12 @@
 "use strict";
 
 let generateTranspiler = require("./babel");
+let { debug } = require("../util");
 let { loadExtension, abort, repr } = require("faucet-pipeline-core/lib/util");
-let commonjs = require("rollup-plugin-commonjs");
-let nodeResolve = require("rollup-plugin-node-resolve");
+let COMMONJS = "rollup-plugin-commonjs";
+let commonjs = require(COMMONJS);
+let NODE_RESOLVE = "rollup-plugin-node-resolve";
+let nodeResolve = require(NODE_RESOLVE);
 
 let MODULE_FORMATS = { // maps faucet identifiers to Rollup identifiers
 	esm: true,
@@ -62,9 +65,11 @@ function generateConfig({ extensions = [], // eslint-disable-next-line indent
 	if(esnext || jsx) {
 		let transpiler = Object.assign({}, esnext, jsx);
 		if(esnext) {
+			debug("ESNext transpilation");
 			transpiler.esnext = true;
 		}
 		if(jsx) {
+			debug("JSX transpilation");
 			// just to be safe, discard JSX-specifics on parent object
 			delete transpiler.pragma;
 			delete transpiler.fragment;
@@ -86,11 +91,15 @@ function generateConfig({ extensions = [], // eslint-disable-next-line indent
 		plugins.push(plugin);
 	}
 	if(typescript) {
-		let ts = loadExtension("rollup-plugin-typescript2",
-				"failed to activate TypeScript", "faucet-pipeline-typescript");
+		debug("TypeScript transpilation");
+		let plugin = "rollup-plugin-typescript2";
+		let ts = loadExtension(plugin, "failed to activate TypeScript",
+				"faucet-pipeline-typescript");
 		extensions.push(".ts");
 		// TODO: provide defaults and abstractions for low-level options?
-		plugins.push(typescript === true ? ts() : ts(typescript));
+		let config = typescript === true ? [] : [typescript]; // spread arguments
+		plugins.push(ts(...config));
+		debug("plugin:", plugin, ...config);
 	}
 
 	let resolve = {
@@ -100,11 +109,13 @@ function generateConfig({ extensions = [], // eslint-disable-next-line indent
 	if(extensions.length) {
 		resolve.extensions = [".js"].concat(extensions);
 	}
+	plugins.push(nodeResolve(resolve));
+	debug("plugin:", NODE_RESOLVE, resolve);
+
+	let _cfg = { include: "node_modules/**" };
+	plugins.push(commonjs(_cfg));
+	debug("plugin:", COMMONJS, _cfg);
 
-	plugins = plugins.concat([
-		nodeResolve(resolve),
-		commonjs({ include: "node_modules/**" })
-	]);
 	if(compact) {
 		cfg.compact = true;
 		plugins = plugins.concat(determineCompacting(compact));
@@ -157,7 +168,9 @@ function determineCompacting(type = true) {
 	switch(type) {
 	case true: // default
 	case "compact":
-		return require("rollup-plugin-cleanup")();
+		var plugin = "rollup-plugin-cleanup"; // eslint-disable-line no-var
+		debug("plugin:", plugin);
+		return require(plugin)();
 	case "minify":
 		var options = { compress: false, mangle: false }; // eslint-disable-line no-var
 		break;
@@ -168,8 +181,10 @@ function determineCompacting(type = true) {
 		abort(`unknown compacting option ${type}`);
 	}
 
-	let { terser } = loadExtension("rollup-plugin-terser",
-			"failed to activate minification", "faucet-pipeline-jsmin");
+	plugin = "rollup-plugin-terser";
+	let { terser } = loadExtension(plugin, "failed to activate minification",
+			"faucet-pipeline-jsmin");
+	debug("plugin:", plugin, options);
 	return terser(options);
 }
 

lib/util.js

@@ -2,6 +2,13 @@
 
 let NOTIFY = '(typeof alert !== "undefined" ? alert : console.error)';
 
+// TODO: move into faucet-core
+exports.DEBUG = process.env.FAUCET_ENV === "DEBUG";
+exports.debug = exports.DEBUG === false ? noop : (...msg) => {
+	msg = msg.map(arg => (arg && !arg.substr) ? JSON.stringify(arg, null, 4) : arg);
+	console.error("[DEBUG]", ...msg);
+};
+
 exports.generateError = err => {
 	let msg = `ERROR: ${err}`;
 	console.error(`✗ ${msg}`);
@@ -28,3 +35,5 @@ function reportCodeFrame(err, prop) {
 	console.error(err);
 	console.error(`\n${frame}\n`);
 }
+
+function noop() {}