Merge pull request #51 from dschweinbenz/fix/usb-listener

fix #50: Solved removing all usb detach listeners

Author: dohooo

.changeset/tidy-ways-flash.md

@@ -0,0 +1,5 @@
+---
+"@node-escpos/usb-adapter": patch
+---
+
+Solved removing all usb detach listeners

packages/usb-adapter/src/index.ts

@@ -23,8 +23,9 @@ export default class USBAdapter extends Adapter<[]> {
 
   constructor(vid?: number | usb.Device, pid?: number) {
     super();
-    // eslint-disable-next-line @typescript-eslint/no-this-alias
-    const self = this;
+    // Bind class reference this to the method
+    this.detachDevice = this.detachDevice.bind(this);
+    
     if (vid && pid && typeof vid === "number") {
       this.device = findByIds(vid, pid) || null;
     }
@@ -45,13 +46,15 @@ export default class USBAdapter extends Adapter<[]> {
     if (!this.device)
       throw new Error("Can not find printer");
 
-    usb.on("detach", (device) => {
-      if (device === self.device) {
-        self.emit("detach", device);
-        self.emit("disconnect", device);
-        self.device = null;
-      }
-    });
+    usb.on("detach", this.detachDevice);
+  }
+
+  private detachDevice(device: usb.Device) {
+    if (device === this.device) {
+      this.emit("detach", device);
+      this.emit("disconnect", device);
+      this.device = null;
+    }
   }
 
   static findPrinter() {
@@ -151,7 +154,7 @@ export default class USBAdapter extends Adapter<[]> {
     if (!this.device) callback?.(new Error("Device not found"));
     try {
       this.device?.close();
-      usb.removeAllListeners("detach");
+      usb.removeListener('detach', this.detachDevice);
       callback && callback(null);
       this.emit("close", this.device);
     }

packages/usb-adapter/test/index.test.ts

@@ -1,7 +1,75 @@
-import { describe, expect, it } from 'vitest'
+import { describe, expect, it, vi } from 'vitest';
+import { Device, usb } from 'usb';
+import USBAdapter from '../src';
+import { promisify } from 'util';
 
 describe('should', () => {
-  it('exported', () => {
-    expect(1).toEqual(1)
-  })
-})
+  it('Validate findPrinter devices', () => {
+    const printers = USBAdapter.findPrinter();
+    if (printers.length > 0) {
+      // Validate printer iface class for all received printers
+      for (const printer of printers) {
+        if (printer.configDescriptor !== undefined) {
+          let hasPrinterClass = false;
+          exit_loop:
+          for (const iface of printer.configDescriptor?.interfaces) {
+            for (const conf of iface) {
+              if (conf.bInterfaceClass === 0x07) {
+                hasPrinterClass = true;
+                break exit_loop;
+              }
+            }
+          }
+          expect(hasPrinterClass).to.be.true;
+        }
+      }
+    }
+  });
+
+  it('Validate adapter listeners', async () => {
+    const printer = new USBAdapter();
+    
+    const handler = vi.fn();
+    printer.addListener('close', handler);
+
+    const openDevice = promisify(printer.open).bind(printer);
+    await openDevice();
+    const closeDevice = promisify(printer.close).bind(printer);
+    await closeDevice();
+
+    expect(handler).toBeCalledTimes(1);
+  });
+
+  it('Validate usb listeners', async () => {
+    let listenerCount = usb.listenerCount('detach');
+    const printer = new USBAdapter();
+    let listenerCountAfter = usb.listenerCount('detach');
+    // Save last recognized listener function for validation
+    const libraryListenerFn = usb.listeners('detach')[listenerCountAfter - 1];
+    expect(listenerCountAfter).to.be.greaterThan(listenerCount);
+
+    // Create custom listener and validate if it still exists after device close
+    listenerCount = listenerCountAfter;
+    function listenerExec() {}
+    usb.on('detach', listenerExec);
+    listenerCountAfter = usb.listenerCount('detach');
+    expect(listenerCountAfter).to.be.greaterThan(listenerCount);
+
+    const openDevice = promisify(printer.open).bind(printer);
+    await openDevice();
+    const closeDevice = promisify(printer.close).bind(printer);
+    await closeDevice(); // Only the internal listener should be removed
+
+    expect(usb.listenerCount('detach')).to.be.lessThan(listenerCountAfter);
+    let libListenerRemoved = true, customListenerStillExist = false;
+    for (const listenerFn of usb.listeners('detach')) {
+      if (listenerFn === libraryListenerFn) {
+        libListenerRemoved = false;
+      } else if (listenerFn === listenerExec) {
+        customListenerStillExist = true;
+      }
+    }
+    expect(libListenerRemoved).to.be.true;
+    expect(customListenerStillExist).to.be.true;
+  });
+});