fix: channel callback never cleaned up from window

.changes/channel-ctor-callback.md

@@ -0,0 +1,5 @@
+---
+"@tauri-apps/api": minor:feat
+---
+
+Allow passing the callback as the parameter of constructor of `Channel` so you can use it like this `new Channel((message) => console.log(message))`

.changes/channel-never-cleaned-up.md

@@ -0,0 +1,6 @@
+---
+"tauri": minor:bug
+"@tauri-apps/api": minor:bug
+---
+
+Fix `Channel`'s callback attached to `window` never cleaned up

.changes/channel-small-payload-perf.md

@@ -0,0 +1,5 @@
+---
+"tauri": minor:perf
+---
+
+Improve `Channel`'s performance when sending small amount of data (e.g. sending a number)

crates/tauri/scripts/core.js

@@ -21,8 +21,8 @@
 
   Object.defineProperty(window.__TAURI_INTERNALS__, 'transformCallback', {
     value: function transformCallback(callback, once) {
-      var identifier = uid()
-      var prop = `_${identifier}`
+      const identifier = uid()
+      const prop = `_${identifier}`
 
       Object.defineProperty(window, prop, {
         value: (result) => {
@@ -56,15 +56,11 @@
   Object.defineProperty(window.__TAURI_INTERNALS__, 'invoke', {
     value: function (cmd, payload = {}, options) {
       return new Promise(function (resolve, reject) {
-        const callback = window.__TAURI_INTERNALS__.transformCallback(function (
-          r
-        ) {
+        const callback = window.__TAURI_INTERNALS__.transformCallback((r) => {
           resolve(r)
           delete window[`_${error}`]
         }, true)
-        const error = window.__TAURI_INTERNALS__.transformCallback(function (
-          e
-        ) {
+        const error = window.__TAURI_INTERNALS__.transformCallback((e) => {
           reject(e)
           delete window[`_${callback}`]
         }, true)

crates/tauri/scripts/process-ipc-message-fn.js

@@ -6,9 +6,9 @@
 
 (function (message) {
   if (
-    message instanceof ArrayBuffer ||
-    ArrayBuffer.isView(message) ||
-    Array.isArray(message)
+    message instanceof ArrayBuffer
+    || ArrayBuffer.isView(message)
+    || Array.isArray(message)
   ) {
     return {
       contentType: 'application/octet-stream',
@@ -27,15 +27,13 @@
         return Array.from(val)
       } else if (val instanceof ArrayBuffer) {
         return Array.from(new Uint8Array(val))
-      } else if (typeof val === "object" && val !== null && SERIALIZE_TO_IPC_FN in val) {
-        return val[SERIALIZE_TO_IPC_FN]()
       } else if (
-        val instanceof Object &&
-        '__TAURI_CHANNEL_MARKER__' in val &&
-        typeof val.id === 'number'
+        typeof val === 'object'
+        && val !== null
+        && SERIALIZE_TO_IPC_FN in val
       ) {
-        return `__CHANNEL__:${val.id}`
-       } else {
+        return val[SERIALIZE_TO_IPC_FN]()
+      } else {
         return val
       }
     })