watcher interface simplifications

src/Graph.ts

@@ -2,6 +2,7 @@ import * as acorn from 'acorn';
 import injectDynamicImportPlugin from 'acorn-dynamic-import/lib/inject';
 import injectImportMeta from 'acorn-import-meta/inject';
 import { Program } from 'estree';
+import { EventEmitter } from 'events';
 import GlobalScope from './ast/scopes/GlobalScope';
 import { EntityPathTracker } from './ast/utils/EntityPathTracker';
 import GlobalVariable from './ast/variables/GlobalVariable';
@@ -22,8 +23,7 @@ import {
 	RollupWarning,
 	SourceDescription,
 	TreeshakingOptions,
-	WarningHandler,
-	Watcher
+	WarningHandler
 } from './rollup/types';
 import { Asset, createAssetPluginHooks, finaliseAsset } from './utils/assetHooks';
 import { load, makeOnwarn, resolveId } from './utils/defaults';
@@ -68,7 +68,7 @@ export default class Graph {
 	// deprecated
 	treeshake: boolean;
 
-	constructor(options: InputOptions, watcher?: Watcher) {
+	constructor(options: InputOptions, watcher?: EventEmitter) {
 		this.curChunkIndex = 0;
 		this.reassignmentTracker = new EntityPathTracker();
 		this.cachedModules = new Map();

src/rollup/index.ts

@@ -1,3 +1,4 @@
+import { EventEmitter } from 'events';
 import { optimizeChunks } from '../chunk-optimization';
 import Graph from '../Graph';
 import { createAddons } from '../utils/addons';
@@ -12,7 +13,6 @@ import mergeOptions, { GenericConfigObject } from '../utils/mergeOptions';
 import { basename, dirname, resolve } from '../utils/path';
 import { SOURCEMAPPING_URL } from '../utils/sourceMappingURL';
 import { getTimings, initialiseTimers, timeEnd, timeStart } from '../utils/timers';
-import { Watcher } from '../watch';
 import {
 	InputOptions,
 	OutputAsset,
@@ -144,8 +144,8 @@ function getInputOptions(rawInputOptions: GenericConfigObject): any {
 	return inputOptions;
 }
 
-let curWatcher: Watcher;
-export function setWatcher(watcher: Watcher) {
+let curWatcher: EventEmitter;
+export function setWatcher(watcher: EventEmitter) {
 	curWatcher = watcher;
 }
 

src/rollup/types.d.ts

@@ -66,7 +66,7 @@ export interface ModuleJSON {
 }
 
 export interface PluginContext {
-	watcher: Watcher;
+	watcher: EventEmitter;
 	resolveId: ResolveIdHook;
 	isExternal: IsExternal;
 	parse: (input: string, options: any) => ESTree.Program;
@@ -351,8 +351,6 @@ export interface RollupOptions extends InputOptions {
 
 export function rollup(options: RollupOptions): Promise<RollupBuild>;
 
-export interface Watcher extends EventEmitter {}
-
 // chokidar watch options
 export interface WatchOptions {
 	persistent?: boolean;
@@ -389,4 +387,8 @@ export interface RollupWatchOptions extends InputOptions {
 	watch?: WatcherOptions;
 }
 
-export function watch(configs: RollupWatchOptions[]): Watcher;
+export interface RollupWatcher extends EventEmitter {
+	close(): void;
+}
+
+export function watch(configs: RollupWatchOptions[]): RollupWatcher;

src/watch/index.ts

@@ -6,10 +6,9 @@ import rollup, { setWatcher } from '../rollup/index';
 import {
 	InputOptions,
 	ModuleJSON,
-	OutputChunk,
 	OutputOptions,
 	RollupBuild,
-	RollupSingleFileBuild,
+	RollupWatcher,
 	RollupWatchOptions
 } from '../rollup/types';
 import ensureArray from '../utils/ensureArray';
@@ -20,27 +19,38 @@ import { addTask, deleteTask } from './fileWatchers';
 
 const DELAY = 200;
 
-export class Watcher extends EventEmitter {
+export class Watcher {
+	emitter: RollupWatcher;
 	private buildTimeout: NodeJS.Timer;
 	private running: boolean;
 	private rerun: boolean = false;
 	private tasks: Task[];
 	private succeeded: boolean = false;
 
 	constructor(configs: RollupWatchOptions[]) {
-		super();
+		this.emitter = new class extends EventEmitter implements RollupWatcher {
+			close: () => void;
+			constructor(close: () => void) {
+				super();
+				this.close = close;
+			}
+		}(this.close.bind(this));
 		this.tasks = ensureArray(configs).map(config => new Task(this, config));
 		this.running = true;
 		process.nextTick(() => this.run());
 	}
 
+	emit(event: string, value: any) {
+		this.emitter.emit(event, value);
+	}
+
 	close() {
 		if (this.buildTimeout) clearTimeout(this.buildTimeout);
 		this.tasks.forEach(task => {
 			task.close();
 		});
 
-		this.removeAllListeners();
+		this.emitter.removeAllListeners();
 	}
 
 	invalidate() {
@@ -194,7 +204,7 @@ export class Task {
 			});
 		}
 
-		setWatcher(this.watcher);
+		setWatcher(this.watcher.emitter);
 		return rollup(options)
 			.then(result => {
 				if (this.closed) return;
@@ -218,11 +228,11 @@ export class Task {
 
 				return Promise.all(
 					this.outputs.map(output => {
-						return <Promise<OutputChunk | Record<string, OutputChunk>>>result.write(output);
+						return result.write(output);
 					})
 				).then(() => result);
 			})
-			.then((result: RollupSingleFileBuild | RollupBuild) => {
+			.then((result: RollupBuild) => {
 				this.watcher.emit('event', {
 					code: 'BUNDLE_END',
 					input: this.inputOptions.input,
@@ -266,5 +276,5 @@ export class Task {
 }
 
 export default function watch(configs: RollupWatchOptions[]) {
-	return new Watcher(configs);
+	return new Watcher(configs).emitter;
 }