fix: replace jsdom/canvas imports with minimal duck-type interfaces

Importing from `jsdom` and `canvas` at the top level of src/types/index.ts,
src/core/QRCodeStyling.ts, and src/core/QRSVG.ts caused browser bundlers to
pull in — or fail to resolve — those Node.js-only packages. Replace all three
with minimal structural interfaces (BrowserWindow, NodeCanvasFactory,
NodeCanvasElement, NodeCanvasImage, JSDOMConstructor) that describe only the
surface the library actually uses, so the build is usable in a browser with
no extraneous Node.js dependencies.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: reaktivo

src/core/QRCodeStyling.ts

@@ -6,10 +6,9 @@ import drawTypes from "../constants/drawTypes";
 
 import defaultOptions, { RequiredOptions } from "./QROptions";
 import sanitizeOptions from "../tools/sanitizeOptions";
-import { FileExtension, QRCode, Options, DownloadOptions, ExtensionFunction, Window } from "../types";
+import { FileExtension, QRCode, Options, DownloadOptions, ExtensionFunction, Window, NodeCanvasElement } from "../types";
 import qrcode from "qrcode-generator";
 import getMimeType from "../tools/getMimeType";
-import { Canvas as NodeCanvas, Image } from "canvas";
 
 declare const window: Window;
 
@@ -18,7 +17,7 @@ export default class QRCodeStyling {
   _window: Window;
   _container?: HTMLElement;
   _domCanvas?: HTMLCanvasElement;
-  _nodeCanvas?: NodeCanvas;
+  _nodeCanvas?: NodeCanvasElement;
   _svg?: SVGElement;
   _qr?: QRCode;
   _extension?: ExtensionFunction;
@@ -79,7 +78,7 @@ export default class QRCodeStyling {
       const image64 = `data:${getMimeType('svg')};base64,${svg64}`;
 
       if (this._options.nodeCanvas?.loadImage) {
-        return this._options.nodeCanvas.loadImage(image64).then((image: Image) => {
+        return this._options.nodeCanvas.loadImage(image64).then((image) => {
           // fix blurry svg
           image.width = this._options.width;
           image.height = this._options.height;

src/core/QRSVG.ts

@@ -7,8 +7,7 @@ import QRCornerDot, { availableCornerDotTypes } from "../figures/cornerDot/QRCor
 import { RequiredOptions } from "./QROptions";
 import gradientTypes from "../constants/gradientTypes";
 import shapeTypes from "../constants/shapeTypes";
-import { DotType, QRCode, FilterFunction, Gradient, Window } from "../types";
-import { Image } from "canvas";
+import { DotType, QRCode, FilterFunction, Gradient, Window, NodeCanvasImage } from "../types";
 
 const squareMask = [
   [1, 1, 1, 1, 1, 1, 1],
@@ -40,7 +39,7 @@ export default class QRSVG {
   _cornersDotClipPath?: SVGElement;
   _options: RequiredOptions;
   _qr?: QRCode;
-  _image?: HTMLImageElement | Image;
+  _image?: HTMLImageElement | NodeCanvasImage;
   _imageUri?: string;
   _instanceId: number;
 
@@ -457,7 +456,7 @@ export default class QRSVG {
       if (options.nodeCanvas?.loadImage) {
         options.nodeCanvas
           .loadImage(options.image)
-          .then((image: Image) => {
+          .then((image) => {
             this._image = image;
             if (this._options.imageOptions.saveAsBlob) {
               const canvas = options.nodeCanvas?.createCanvas( this._image.width,  this._image.height);

src/types/index.ts

@@ -1,6 +1,3 @@
-import { DOMWindow, JSDOM } from "jsdom";
-import nodeCanvas  from "canvas";
-
 export interface UnknownObject {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   [key: string]: any;
@@ -14,7 +11,44 @@ export type GradientType = "radial" | "linear";
 export type DrawType = "canvas" | "svg";
 export type ShapeType = "square" | "circle";
 
-export type Window = DOMWindow;
+// Minimal window-like interface — compatible with both browser Window and jsdom DOMWindow
+export interface BrowserWindow {
+  document: Document;
+  XMLSerializer: typeof XMLSerializer;
+  Image: { new(): HTMLImageElement };
+  XMLHttpRequest: typeof XMLHttpRequest;
+  FileReader: typeof FileReader;
+}
+
+export type Window = BrowserWindow;
+
+// Minimal node-canvas interfaces — avoids importing the "canvas" package in browser bundles
+export interface NodeCanvasImage {
+  width: number;
+  height: number;
+}
+
+export interface NodeCanvasRenderingContext2D {
+  drawImage(image: NodeCanvasImage, dx: number, dy: number): void;
+}
+
+export interface NodeCanvasElement {
+  width: number;
+  height: number;
+  getContext(contextId: "2d"): NodeCanvasRenderingContext2D | null;
+  toBuffer(mimeType: string): Buffer;
+  toDataURL(type?: string): string;
+}
+
+export interface NodeCanvasFactory {
+  createCanvas(width: number, height: number): NodeCanvasElement;
+  loadImage(src: string): Promise<NodeCanvasImage>;
+}
+
+// Minimal jsdom constructor interface — avoids importing "jsdom" in browser bundles
+export interface JSDOMConstructor {
+  new(html: string, options?: { resources?: string }): { window: BrowserWindow };
+}
 
 export type Gradient = {
   type: GradientType;
@@ -116,8 +150,8 @@ export type Options = {
   margin?: number;
   data?: string;
   image?: string;
-  nodeCanvas?: typeof nodeCanvas;
-  jsdom?: typeof JSDOM;
+  nodeCanvas?: NodeCanvasFactory;
+  jsdom?: JSDOMConstructor;
   qrOptions?: {
     typeNumber?: TypeNumber;
     mode?: Mode;