fix: Add cache value on Widget class.

examples/widgets.js

@@ -14,6 +14,19 @@ if (cameraList.size) {
   console.log(camera.toString());
   console.log(camera.widgets.toString());
 
+  // change value
+  camera.widgets.get('/actions/autofocusdrive').value = true;
+  camera.widgets.get('/settings/autofocus').value = 'on';
+
+  // OR apply
+  camera.widgets.apply({
+    '/actions/autofocusdrive': true,
+    '/settings/autofocus': 'on'
+  });
+
+  console.log('/actions/autofocusdrive', camera.widgets.get('/actions/autofocusdrive').value);
+  console.log('/settings/autofocus', camera.widgets.get('/settings/autofocus').value);
+
   // camera.widgets => Widget which inherit from Map class
   const widgets = JSON.stringify(camera.widgets, null, 2);
   fs.writeFileSync('../.tmp/widgets.json', widgets, { encoding: 'utf8' });

package.json

@@ -74,4 +74,4 @@
   "release": {
     "branch": "production"
   }
-}
+}

src/components/CameraWidgets.ts

@@ -98,10 +98,19 @@ export class CameraWidgets extends Map<string, Widget> implements ICloseable {
 
   /**
    * If the settings are altered, they need to be applied to take effect.
+   *
+   * @param obj An object to define a group of configuration
    */
-  apply() {
+  apply(obj?: any) {
     this.checkNotClosed();
-    checkCode(GPhoto2Driver.gp_camera_set_config(this.camera.pointer, this.rootWidget, Context.get().pointer), "gp_camera_set_config");
+
+    if (obj) {
+      Object.keys(obj).forEach(key => {
+        this.get(key).value = obj[key];
+      });
+    } else {
+      checkCode(GPhoto2Driver.gp_camera_set_config(this.camera.pointer, this.rootWidget, Context.get().pointer), "gp_camera_set_config");
+    }
   }
 
   close(): this {

src/components/Widget.ts

@@ -1,12 +1,14 @@
 import {checkCode, GPhoto2Driver, GPPointerFloat, GPPointerInt, GPPointerRef, GPPointerString, PointerToString} from "../driver";
 import {PointerCameraWidget} from "../driver/modules";
 import {PointerOf} from "../driver/types";
-import {classOf} from "../driver/utils/ObjectUtils";
+import {nameOf} from "../driver/utils/ObjectUtils";
 import {IWidget} from "../interfaces";
 import {WidgetRange} from "./WidgetRange";
 import {WidgetTypes} from "./WidgetTypes";
 
 export class Widget implements IWidget {
+  cachedValue: any;
+
   constructor(readonly path: string, readonly pointer: PointerCameraWidget, private cameraWidgets: any) {}
 
   /**
@@ -86,6 +88,10 @@ export class Widget implements IWidget {
 
     const type = this.type;
 
+    if (this.cachedValue) {
+      return this.cachedValue;
+    }
+
     switch (type) {
       case WidgetTypes.TEXT:
       case WidgetTypes.RADIO:
@@ -122,7 +128,7 @@ export class Widget implements IWidget {
         return null;
 
       default:
-        throw new Error("Parameter path: invalid value " + name + ": unsupported type: " + type);
+        throw new Error("Parameter path: invalid value " + this.path + ": unsupported type: " + type);
     }
   }
 
@@ -136,14 +142,14 @@ export class Widget implements IWidget {
     this.cameraWidgets.checkNotClosed();
 
     if (this.readonly) {
-      throw new Error(`Parameter name: invalid value ${name}: read-only`);
+      throw new Error(`Parameter name: invalid value ${this.path} [read-only]`);
     }
 
     const type = this.type;
 
     if (!type.acceptsValue(value)) {
       throw new Error(
-        `Parameter value: invalid value ${value}: expected ${type.valueType} but got ${value == null ? "null" : classOf(value)}`
+        `Parameter value: invalid value ${value}: expected ${nameOf(type.valueType)} but got ${value == null ? "null" : nameOf(value)}`
       );
     }
 
@@ -183,7 +189,12 @@ export class Widget implements IWidget {
 
     checkCode(GPhoto2Driver.gp_widget_set_value(this.pointer, ptr as PointerOf<any>));
 
-    this.apply();
+    try {
+      this.apply();
+      this.cachedValue = value;
+    } catch (er) {
+      throw new Error(`Parameter value: failed to apply value ${value} on ${this.path}. \nError: ` + er.message);
+    }
   }
 
   get changed(): boolean {