Merge pull request #13 from msgpack/async-decoder

Introduce decodeAsync() for streaming decoding

Author: gfx

README.md

@@ -15,7 +15,7 @@ import { deepStrictEqual } from "assert";
 import { encode, decode } from "@msgpack/msgpack";
 
 const object = {
- nullOrUndefined: null,
+ nil: null,
  integer: 1,
  float: Math.PI,
  string: "Hello, world!",
@@ -39,6 +39,20 @@ This library is publised as [@msgpack/msgpack](https://www.npmjs.com/package/@ms
 npm install @msgpack/msgpack
 ```
 
+## Encode and Decode
+
+### `encode(data: unknown, options?): Uint8Array`
+
+It encodes `data` and returns a byte array as `Uint8Array`.
+
+### `decode(buffer: ArrayLike<number> | Uint8Array, options?): unknown`
+
+It decodes `buffer` in a byte buffer and returns decoded data as `uknown`.
+
+### `decodeAsync(stream: AsyncIterable<ArrayLike<number> | Uint8Array>, options?): Promise<unknown>`
+
+It decodes `stream` in an async iterable of byte arrays and returns decoded data as `uknown` wrapped in `Promise`. This function works asyncronously.
+
 ## Extension Types
 
 To handle [MessagePack Extension Types](https://github.com/msgpack/msgpack/blob/master/spec.md#extension-types), this library provides `ExtensionCodec` class.
@@ -105,17 +119,17 @@ If you use this library in NodeJS, v10 or later is required.
 
 ## Benchmark
 
-Benchmark on NodeJS/v12.1.0 (macOS 10.14.4):
+Benchmark on NodeJS/v12.1.0
 
 operation | op | ms | op/s
 ----------------------------------------------------------------- | ------: | ----: | ------:
-buf = Buffer.from(JSON.stringify(obj)); | 496800 | 5000 | 99360
-buf = JSON.stringify(obj); | 911800 | 5000 | 182360
-obj = JSON.parse(buf); | 350600 | 5000 | 70120
-buf = require("msgpack-lite").encode(obj); | 350900 | 5000 | 70180
-obj = require("msgpack-lite").decode(buf); | 270800 | 5000 | 54160
-buf = require("@msgpack/msgpack").encode(obj); | 576700 | 5000 | 115340
-obj = require("@msgpack/msgpack").decode(buf); | 340800 | 5001 | 68146
+buf = Buffer.from(JSON.stringify(obj)); | 493600 | 5000 | 98720
+buf = JSON.stringify(obj); | 959600 | 5000 | 191920
+obj = JSON.parse(buf); | 346100 | 5000 | 69220
+buf = require("msgpack-lite").encode(obj); | 358300 | 5000 | 71660
+obj = require("msgpack-lite").decode(buf); | 270400 | 5000 | 54080
+buf = require("@msgpack/msgpack").encode(obj); | 594300 | 5000 | 118860
+obj = require("@msgpack/msgpack").decode(buf); | 343100 | 5000 | 68620
 
 ## Distrubition
 

benchmark/profile-decode.ts

@@ -1,16 +1,24 @@
-import { encode, decode } from "../src";
+import { encode, decode, decodeAsync } from "../src";
 
 const data = require("./benchmark-from-msgpack-lite-data.json");
 const encoded = encode(data);
 
+console.log("encoded size:", encoded.byteLength);
+
 console.time("decode #1");
 for (let i = 0; i < 10000; i++) {
  decode(encoded);
 }
 console.timeEnd("decode #1");
 
-console.time("decode #2");
-for (let i = 0; i < 10000; i++) {
- decode(encoded);
-}
-console.timeEnd("decode #2");
+(async () => {
+ const buffers = async function*() {
+ yield encoded;
+ };
+
+ console.time("decodeAsync #1");
+ for (let i = 0; i < 10000; i++) {
+ await decodeAsync(buffers());
+ }
+ console.timeEnd("decodeAsync #1");
+})();

benchmark/sync-vs-async.ts

@@ -0,0 +1,42 @@
+#!ts-node
+/* eslint-disable no-console */
+
+import { encode, decode, decodeAsync } from "../src";
+import { writeFileSync, unlinkSync, readFileSync, createReadStream } from "fs";
+import { deepStrictEqual } from "assert";
+
+(async () => {
+ const data = [];
+ for (let i = 0; i < 1000; i++) {
+ const id = i + 1;
+ data.push({
+ id,
+ score: Math.round(Math.random() * Number.MAX_SAFE_INTEGER),
+ title: `Hello, world! #${id}`,
+ content: `blah blah blah `.repeat(20).trim(),
+ createdAt: new Date(),
+ });
+ }
+ const encoded = encode(data);
+ const file = "benchmark/tmp.msgpack";
+ writeFileSync(file, encoded);
+ process.on("exit", () => unlinkSync(file));
+ console.log(`encoded size ${Math.round(encoded.byteLength / 1024)}KiB`);
+
+ deepStrictEqual(decode(readFileSync(file)), data);
+ deepStrictEqual(await decodeAsync(createReadStream(file)), data);
+
+ // sync
+ console.time("readFileSync |> decode");
+ for (let i = 0; i < 100; i++) {
+ decode(readFileSync(file));
+ }
+ console.timeEnd("readFileSync |> decode");
+
+ // async
+ console.time("creteReadStream |> decodeAsync");
+ for (let i = 0; i < 100; i++) {
+ await decodeAsync(createReadStream(file));
+ }
+ console.timeEnd("creteReadStream |> decodeAsync");
+})();