event-iterator - npm Package Compare versions

Comparing version 1.1.0 to 1.2.0

lib/dom.d.ts

@@ -1,4 +0,4 @@
-import { EventIterator } from "./event-iterator";
-export declare function subscribe(this: EventTarget, event: string, options?: AddEventListenerOptions): EventIterator<Event>;
+import { EventIterator, EventIteratorOptions } from "./event-iterator";
+export declare function subscribe(this: EventTarget, event: string, options?: AddEventListenerOptions, evOptions?: EventIteratorOptions): EventIterator<Event>;
 export { EventIterator };
 export default EventIterator;

lib/dom.js

@@ -5,3 +5,3 @@ "use strict";
 exports.EventIterator = event_iterator_1.EventIterator;
-function subscribe(event, options) {
+function subscribe(event, options, evOptions) {
     return new event_iterator_1.EventIterator((push) => {
@@ -11,5 +11,5 @@ this.addEventListener(event, push, options);
         this.removeEventListener(event, push, options);
-    });
+    }, evOptions);
 }
 exports.subscribe = subscribe;
 exports.default = event_iterator_1.EventIterator;

lib/event-iterator.d.ts

@@ -6,8 +6,12 @@ export declare type PushCallback<T> = (res: T) => void;
 export declare type RemoveHandler<T> = (push: PushCallback<T>, stop: StopCallback<T>, fail: FailCallback<T>) => void;
+export interface EventIteratorOptions {
+    highWaterMark?: number;
+}
 export declare class EventIterator<T> implements AsyncIterable<T> {
     private listen;
     private remove?;
-    constructor(listen: ListenHandler<T>, remove?: RemoveHandler<T>);
+    private options;
+    constructor(listen: ListenHandler<T>, remove?: RemoveHandler<T>, options?: EventIteratorOptions);
     [Symbol.asyncIterator](): AsyncIterator<T>;
 }
 export default EventIterator;

lib/event-iterator.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 class EventIterator {
-    constructor(listen, remove) {
+    constructor(listen, remove, options = {}) {
         this.listen = listen;
         this.remove = remove;
+        this.options = Object.assign({ highWaterMark: 100 }, options);
         Object.freeze(this);
@@ -22,4 +23,5 @@ }
                 queue.push(Promise.resolve(resolution));
-                if (queue.length > 100 && console) {
-                    console.warn("EventIterator queue filling up");
+                const { highWaterMark } = this.options;
+                if (highWaterMark !== undefined && queue.length >= highWaterMark && console) {
+                    console.warn(`EventIterator queue reached ${queue.length} items`);
                 }
@@ -26,0 +28,0 @@ }

lib/node.d.ts

 /// <reference types="node" />
 import { Readable } from "stream";
-import { EventIterator } from "./event-iterator";
-export declare function stream(this: Readable): EventIterator<Buffer>;
+import { EventIterator, EventIteratorOptions } from "./event-iterator";
+export declare function stream(this: Readable, evOptions?: EventIteratorOptions): EventIterator<Buffer>;
 export { EventIterator };
 export default EventIterator;

lib/node.js

@@ -5,3 +5,3 @@ "use strict";
 exports.EventIterator = event_iterator_1.EventIterator;
-function stream() {
+function stream(evOptions) {
     return new event_iterator_1.EventIterator((push, stop, fail) => {
@@ -22,5 +22,5 @@ this.addListener("data", push);
         }
-    });
+    }, evOptions);
 }
 exports.stream = stream;
 exports.default = event_iterator_1.EventIterator;

package.json

 {
   "name": "event-iterator",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "Convert event emitters and event targets to ES async iterators",
@@ -35,4 +35,4 @@ "homepage": "https://github.com/rolftimmermans/event-iterator",
   "scripts": {
-    "test": "mocha && rm -rf lib && tsc"
+    "test": "mocha test/*-test.ts && rm -rf lib && tsc"
   }
 }

README.md

@@ -115,4 +115,7 @@ # EventIterator: convert any JS event emitter to async iterators
 
+/* High water mark defaults to 100. Set to undefined to disable warnings. */
+interface EventIteratorOptions = {highWatermark?: number }
+
 class EventIterator<T> {
-    constructor(ListenHandler<T>, ?RemoveHandler<T>)
+    constructor(ListenHandler<T>, ?RemoveHandler<T>, ?EventIteratorOptions)
 
@@ -286,2 +289,3 @@ [Symbol.asyncIterator](): AsyncIterator<T>
 async iterator; the internal `EventIterator` queue will fill up indefinitely.
+A warning will be emitted when the queue reaches 100 items.
 
@@ -294,8 +298,19 @@ One example is reading each line from a file with `stream()` and executing a
 
+The limit can be changed or disabled by settings `highWaterMark` in the options
+of the  `EventIterator` constructor.
+
 A next version may support an optional API to pause/resume if the queue becomes
 too long.
 
+## Changes
+
+1.2.0:
+* Add options argument to constructor, allowing configuration of `highWaterMark` (@alanshaw).
+
+1.1.0:
+* First stable version.
+
 ## Licensed under MIT license
 
-Copyright (c) 2017 Rolf Timmermans
+Copyright (c) 2017-2019 Rolf Timmermans
 
@@ -302,0 +317,0 @@ Permission is hereby granted, free of charge, to any person obtaining a copy

src/dom.ts

@@ -1,4 +0,4 @@
-import {EventIterator} from "./event-iterator"
+import {EventIterator, EventIteratorOptions} from "./event-iterator"
 
-export function subscribe(this: EventTarget, event: string, options?: AddEventListenerOptions) {
+export function subscribe(this: EventTarget, event: string, options?: AddEventListenerOptions, evOptions?: EventIteratorOptions) {
   return new EventIterator<Event>(
@@ -12,2 +12,4 @@ (push) => {
     },
+
+    evOptions,
   )
@@ -14,0 +16,0 @@ }

src/event-iterator.ts

@@ -8,2 +8,6 @@ export type PushCallback<T> = (res: T) => void
 
+export interface EventIteratorOptions {
+  highWaterMark?: number
+}
+
 type AsyncResolver<T> = {
@@ -19,6 +23,8 @@ resolve: (res: IteratorResult<T>) => void
   private remove?: RemoveHandler<T>
+  private options: EventIteratorOptions
 
-  constructor(listen: ListenHandler<T>, remove?: RemoveHandler<T>) {
+  constructor(listen: ListenHandler<T>, remove?: RemoveHandler<T>, options: EventIteratorOptions = {}) {
     this.listen = listen
     this.remove = remove
+    this.options = {highWaterMark: 100, ...options}
     Object.freeze(this)
@@ -40,4 +46,5 @@ }
         queue.push(Promise.resolve(resolution))
-        if (queue.length > 100 && console) {
-          console.warn("EventIterator queue filling up")
+        const {highWaterMark} = this.options
+        if (highWaterMark !== undefined && queue.length >= highWaterMark && console) {
+          console.warn(`EventIterator queue reached ${queue.length} items`)
         }
@@ -44,0 +51,0 @@ }

src/node.ts

 import {Readable} from "stream"
-import {EventIterator} from "./event-iterator"
+import {EventIterator, EventIteratorOptions} from "./event-iterator"
 
-export function stream(this: Readable) {
+export function stream(this: Readable, evOptions?: EventIteratorOptions) {
   return new EventIterator<Buffer>(
@@ -24,2 +24,4 @@ (push, stop, fail) => {
     },
+
+    evOptions,
   )
@@ -26,0 +28,0 @@ }

test/event-iterator-test.ts

@@ -154,2 +154,64 @@ import "./symbol-polyfill"
   })
+
+  describe("with high water mark", function() {
+    it("should warn", async function() {
+      const oldconsole = console
+      const log = global.console = new MemoryConsole
+
+      const it = new EventIterator(next => {next("val")}, undefined, {highWaterMark: 1})
+
+      await new Promise(setImmediate)
+      const result = await it[Symbol.asyncIterator]().next()
+
+      global.console = oldconsole
+
+      assert.equal(log.stderr.toString(), "EventIterator queue reached 1 items\n")
+    })
+  })
 })
+
+import {Console} from "console"
+import {Writable} from "stream"
+
+export class BufferStream extends Writable {
+  private readonly buffers: Buffer[] = []
+
+  _write(chunk: Buffer | string, encoding: string, callback: (err?: Error) => void) {
+    if (typeof chunk === "string") chunk = Buffer.from(chunk)
+    this.buffers.push(chunk)
+    callback()
+    return true
+  }
+
+  clear() {
+    this.buffers.length = 0
+  }
+
+  inspect() {
+    return Buffer.concat(this.buffers).toString()
+  }
+
+  toString() {
+    return Buffer.concat(this.buffers).toString()
+  }
+}
+
+export class MemoryConsole extends Console {
+  stdout: BufferStream
+  stderr: BufferStream
+
+  constructor() {
+    const stdout = new BufferStream
+    const stderr = new BufferStream
+    super(stdout, stderr)
+
+    this.stdout = stdout
+    this.stderr = stderr
+    Object.freeze(this)
+  }
+
+  clear() {
+    this.stdout.clear()
+    this.stderr.clear()
+  }
+}

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Improved metrics

Total package byte prevSize

29964

increased by10.42%

Lines of code

561

increased by12.2%

Number of lines in readme file

331

increased by4.75%

No dependency changes