perf: ⚡️ use new BufferList

Author: streamich

benchmarks/bench.js

@@ -0,0 +1,28 @@
+const Benchmark = require('benchmark');
+const packets = require('./packets');
+const {MqttDecoder} = require('../es6/MqttDecoder');
+const mqtt = require('mqtt-packet');
+
+const suite = new Benchmark.Suite;
+
+suite
+  .add(`mqtt-codec`, function() {
+    const decoder = new MqttDecoder();
+    for (const name of Object.keys(packets)) {
+      decoder.push(Buffer.from(packets[name]));
+      decoder.parse();
+    }
+  })
+  .add(`mqtt-packet`, function() {
+    const parser = mqtt.parser();
+    for (const name of Object.keys(packets)) {
+      parser.parse(Buffer.from(packets[name]));
+    }
+  })
+  .on('cycle', function(event) {
+    console.log(String(event.target));
+  })
+  .on('complete', function() {
+    console.log('Fastest is ' + this.filter('fastest').map('name'));
+  })
+  .run();

benchmarks/test.js

@@ -33,9 +33,7 @@
     "release": "semantic-release"
   },
   "keywords": [],
-  "dependencies": {
-    "bl": "^4.0.3"
-  },
+  "dependencies": {},
   "peerDependencies": {
     "tslib": "2"
   },

package.json

@@ -13,7 +13,13 @@ export class BufferList {
   public consume(size: number) {
     this.offset += size;
     this.length -= size;
-    while (this.offset >= this.list[0].length) {
+    if (this.length < 0) {
+      this.list = [];
+      this.offset = 0;
+      this.length = 0;
+      return;
+    }
+    while (this.list.length && this.offset >= this.list[0].length) {
       this.offset -= this.list[0].length;
       this.list.shift();
     }

src/BufferList.ts

@@ -1,4 +1,4 @@
-import BufferList from 'bl';
+import {BufferList} from './BufferList';
 import {ERROR, PACKET_TYPE} from './enums';
 import {PacketConnack, parseConnack} from './packets/connack';
 import {PacketConnect, parseConnect} from './packets/connect';

src/MqttDecoder.ts

@@ -94,12 +94,22 @@ it('can consume bytes in multiple blocks', () => {
   expect(list.readUInt8(0)).toBe(3);
 });
 
-it('consuming out-of-bounds throws error', () => {
+it('consuming out-of-bounds is a no-op', () => {
   const list = new BufferList();
   list.append(Buffer.from([1, 2, 3]));
+  expect(list.length).toBe(3);
+  list.consume(1);
+  expect(list.length).toBe(2);
+  list.consume(1);
+  expect(list.length).toBe(1);
+  list.consume(1);
+  expect(list.length).toBe(0);
   list.consume(1);
+  expect(list.length).toBe(0);
   list.consume(1);
-  expect(() => list.consume(1)).toThrowError();
+  expect(list.length).toBe(0);
+  list.consume(10);
+  expect(list.length).toBe(0);
 });
 
 it('can read ui16', () => {
@@ -126,7 +136,8 @@ it('can read ui16 from adjacent buffers', () => {
   list.consume(1);
   expect(list.readUInt16BE(0)).toBe(256);
   list.consume(1);
-  expect(() => list.consume(1)).toThrowError();
+  list.consume(123);
+  expect(list.length).toBe(0);
 });
 
 it('can read ui32 from adjacent buffers', () => {

src/__tests__/BufferList.spec.ts

@@ -1,5 +1,5 @@
 import {MqttDecoder} from '../MqttDecoder';
-import {connect, connectAck, connectWithClientId, publish3111, subscribe, subscribeAck} from './util';
+import {connect, connectAck, connectWithClientId, publish3111} from './util';
 import {ERROR, PACKET_TYPE, PROPERTY} from '../enums';
 import {PacketConnect} from '../packets/connect';
 import {PacketConnack} from '../packets/connack';

src/__tests__/MqttDecoder.spec.ts

@@ -1 +1,2 @@
-export const hello = () => 'world';
+export * from './types';
+export * from './MqttDecoder';

src/index.ts

@@ -1,4 +1,4 @@
-import BufferList from 'bl';
+import {BufferList} from '../BufferList';
 import {Packet, PacketHeaderData} from '../packet';
 import {Properties} from '../types';
 import {parseProps} from '../util/parse';

src/packets/auth.ts

@@ -1,7 +1,7 @@
-import BufferList from 'bl';
+import {BufferList} from '../BufferList';
 import {Packet, PacketHeaderData} from '../packet';
-import {Properties, QoS} from '../types';
-import {parseProps, parseBinary} from '../util/parse';
+import {Properties} from '../types';
+import {parseProps} from '../util/parse';
 
 export interface PacketConnackData extends PacketHeaderData {
   /** Connect Acknowledge Flags. */