feat: move binary detection back to the parser

The binary detection was moved from the parser to the client/server in
[1], in order to allow the user to skip the binary detection for huge
JSON payloads.

```js
socket.binary(false).emit(...);
```

The binary detection is needed in the default parser, because the
payload is encoded with JSON.stringify(), which does not support binary
content (ArrayBuffer, Blob, ...).

But other parsers (like [2] or [3]) do not need this check, so we'll
move the binary detection back here and remove the socket.binary()
method, as this use case is now covered by the ability to provide your
own parser.

Note: the hasBinary method was copied from [4].

[1]: f44256c
[2]: https://github.com/darrachequesne/socket.io-msgpack-parser
[3]: https://github.com/darrachequesne/socket.io-json-parser
[4]: https://github.com/darrachequesne/has-binary

lib/binary.ts

@@ -1,4 +1,4 @@
-import isBinary from "./is-binary";
+import { isBinary } from "./is-binary";
 
 /**
  * Replaces every Buffer | ArrayBuffer | Blob | File in packet with a numbered placeholder.

lib/index.ts

@@ -1,6 +1,6 @@
-import Emitter from "component-emitter";
+import Emitter = require("component-emitter");
 import { deconstructPacket, reconstructPacket } from "./binary";
-import isBinary from "./is-binary";
+import { isBinary, hasBinary } from "./is-binary";
 
 const debug = require("debug")("socket.io-parser");
 
@@ -44,15 +44,16 @@ export class Encoder {
   public encode(obj: Packet) {
     debug("encoding packet %j", obj);
 
-    if (
-      obj.type === PacketType.BINARY_EVENT ||
-      obj.type === PacketType.BINARY_ACK
-    ) {
-      return this.encodeAsBinary(obj);
-    } else {
-      const encoding = this.encodeAsString(obj);
-      return [encoding];
+    if (obj.type === PacketType.EVENT || obj.type === PacketType.ACK) {
+      if (hasBinary(obj)) {
+        obj.type =
+          obj.type === PacketType.EVENT
+            ? PacketType.BINARY_EVENT
+            : PacketType.BINARY_ACK;
+        return this.encodeAsBinary(obj);
+      }
     }
+    return [this.encodeAsString(obj)];
   }
 
   /**

lib/is-binary.ts

@@ -1,5 +1,3 @@
-const withNativeBuffer: boolean =
-  typeof Buffer === "function" && typeof Buffer.isBuffer === "function";
 const withNativeArrayBuffer: boolean = typeof ArrayBuffer === "function";
 
 const isView = (obj: any) => {
@@ -24,11 +22,45 @@ const withNativeFile =
  * @private
  */
 
-export default function isBinary(obj: any) {
+export function isBinary(obj: any) {
   return (
-    (withNativeBuffer && Buffer.isBuffer(obj)) ||
     (withNativeArrayBuffer && (obj instanceof ArrayBuffer || isView(obj))) ||
     (withNativeBlob && obj instanceof Blob) ||
     (withNativeFile && obj instanceof File)
   );
 }
+
+export function hasBinary(obj: any, toJSON?: boolean) {
+  if (!obj || typeof obj !== "object") {
+    return false;
+  }
+
+  if (Array.isArray(obj)) {
+    for (let i = 0, l = obj.length; i < l; i++) {
+      if (hasBinary(obj[i])) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  if (isBinary(obj)) {
+    return true;
+  }
+
+  if (
+    obj.toJSON &&
+    typeof obj.toJSON === "function" &&
+    arguments.length === 1
+  ) {
+    return hasBinary(obj.toJSON(), true);
+  }
+
+  for (const key in obj) {
+    if (Object.prototype.hasOwnProperty.call(obj, key) && hasBinary(obj[key])) {
+      return true;
+    }
+  }
+
+  return false;
+}

test/arraybuffer.js

@@ -6,7 +6,7 @@ const encoder = new Encoder();
 describe("parser", () => {
   it("encodes an ArrayBuffer", (done) => {
     const packet = {
-      type: PacketType.BINARY_EVENT,
+      type: PacketType.EVENT,
       data: ["a", new ArrayBuffer(2)],
       id: 0,
       nsp: "/",
@@ -19,7 +19,7 @@ describe("parser", () => {
     for (let i = 0; i < array.length; i++) array[i] = i;
 
     const packet = {
-      type: PacketType.BINARY_EVENT,
+      type: PacketType.EVENT,
       data: ["a", array],
       id: 0,
       nsp: "/",
@@ -29,7 +29,7 @@ describe("parser", () => {
 
   it("encodes ArrayBuffers deep in JSON", (done) => {
     const packet = {
-      type: PacketType.BINARY_EVENT,
+      type: PacketType.EVENT,
       data: [
         "a",
         {
@@ -46,7 +46,7 @@ describe("parser", () => {
 
   it("encodes deep binary JSON with null values", (done) => {
     const packet = {
-      type: PacketType.BINARY_EVENT,
+      type: PacketType.EVENT,
       data: ["a", { a: "b", c: 4, e: { g: null }, h: new ArrayBuffer(9) }],
       nsp: "/",
       id: 600,
@@ -56,7 +56,7 @@ describe("parser", () => {
 
   it("cleans itself up on close", () => {
     const packet = {
-      type: PacketType.BINARY_EVENT,
+      type: PacketType.EVENT,
       data: ["a", new ArrayBuffer(2), new ArrayBuffer(3)],
       id: 0,
       nsp: "/",

test/blob.js

@@ -24,7 +24,7 @@ describe("parser", () => {
     }
 
     const packet = {
-      type: PacketType.BINARY_EVENT,
+      type: PacketType.EVENT,
       data: ["a", data],
       id: 0,
       nsp: "/",
@@ -43,7 +43,7 @@ describe("parser", () => {
     }
 
     const packet = {
-      type: PacketType.BINARY_EVENT,
+      type: PacketType.EVENT,
       data: ["a", { a: "hi", b: { why: data }, c: "bye" }],
       id: 999,
       nsp: "/deep",
@@ -62,7 +62,7 @@ describe("parser", () => {
     }
 
     const packet = {
-      type: PacketType.BINARY_ACK,
+      type: PacketType.ACK,
       data: [{ a: "hi ack", b: { why: data }, c: "bye ack" }],
       id: 999,
       nsp: "/deep",

test/buffer.js

@@ -5,7 +5,7 @@ describe("parser", () => {
   it("encodes a Buffer", (done) => {
     helpers.test_bin(
       {
-        type: PacketType.BINARY_EVENT,
+        type: PacketType.EVENT,
         data: ["a", Buffer.from("abc", "utf8")],
         id: 23,
         nsp: "/cool",
@@ -17,7 +17,7 @@ describe("parser", () => {
   it("encodes a binary ack with Buffer", (done) => {
     helpers.test_bin(
       {
-        type: PacketType.BINARY_ACK,
+        type: PacketType.ACK,
         data: ["a", Buffer.from("xxx", "utf8"), {}],
         id: 127,
         nsp: "/back",

tsconfig.json

@@ -4,8 +4,7 @@
     "allowJs": false,
     "target": "es2017",
     "module": "commonjs",
-    "declaration": true,
-    "esModuleInterop": true
+    "declaration": true
   },
   "include": [
     "./lib/**/*"