print nice build summaries

src/core/create_compilers.ts

@@ -1,7 +1,10 @@
 import * as fs from 'fs';
 import * as path from 'path';
+import colors from 'kleur';
+import pb from 'pretty-bytes';
 import { locations } from '../config';
 import relative from 'require-relative';
+import { left_pad, right_pad } from '../utils';
 
 let r: any;
 let wp: any;
@@ -20,6 +23,8 @@ export class CompileResult {
 }
 
 class RollupResult extends CompileResult {
+	summary: string;
+
 	constructor(duration: number, compiler: RollupCompiler) {
 		super();
 
@@ -39,10 +44,51 @@ class RollupResult extends CompileResult {
 				this.assetsByChunkName.main = chunk.fileName;
 			}
 		});
+
+		this.summary = compiler.chunks.map(chunk => {
+			const size_color = chunk.code.length > 150000 ? colors.bold.red : chunk.code.length > 50000 ? colors.bold.yellow : colors.bold.white;
+			const size_label = left_pad(pb(chunk.code.length), 10);
+
+			const lines = [size_color(`${size_label} ${chunk.fileName}`)];
+
+			const deps = Object.keys(chunk.modules)
+				.map(file => {
+					return {
+						file: path.relative(process.cwd(), file),
+						size: chunk.modules[file].renderedLength
+					};
+				})
+				.filter(dep => dep.size > 0)
+				.sort((a, b) => b.size - a.size);
+
+			const total_unminified = deps.reduce((t, d) => t + d.size, 0);
+
+			deps.forEach((dep, i) => {
+				const c = i === deps.length - 1 ? '└' : '│';
+				let line = `           ${c} ${dep.file}`;
+
+				if (deps.length > 1) {
+					const p = (100 * dep.size / total_unminified).toFixed(1);
+					line += ` (${p}%)`;
+				}
+
+				lines.push(colors.gray(line));
+			});
+
+			return lines.join('\n');
+		}).join('\n');
 	}
 
 	print() {
-		return 'TODO summarise build';
+		const blocks: string[] = this.warnings.map(warning => {
+			return warning.file
+				? `> ${colors.bold(warning.file)}\n${warning.message}`
+				: `> ${warning.message}`;
+		});
+
+		blocks.push(this.summary);
+
+		return blocks.join('\n\n');
 	}
 }
 
@@ -148,10 +194,23 @@ export class RollupCompiler {
 
 		const start = Date.now();
 
-		const bundle = await r.rollup(config);
-		await bundle.write(config.output);
+		try {
+			const bundle = await r.rollup(config);
+			await bundle.write(config.output);
 
-		return new RollupResult(Date.now() - start, bundle);
+			return new RollupResult(Date.now() - start, this);
+		} catch (err) {
+			if (err.filename) {
+				// TODO this is a bit messy. Also, can
+				// Rollup emit other kinds of error?
+				err.message = [
+					`Failed to build — error in ${err.filename}: ${err.message}`,
+					err.frame
+				].filter(Boolean).join('\n');
+			}
+
+			throw err;
+		}
 	}
 
 	async watch(cb: (err?: Error, stats?: any) => void) {