Update README.md

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "jscanify",
-  "version": "1.2.0",
+  "version": "1.3.3",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "jscanify",
-      "version": "1.2.0",
+      "version": "1.3.3",
       "license": "MIT",
       "dependencies": {
         "canvas": "^2.11.2",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "jscanify",
-  "version": "1.3.2",
+  "version": "1.3.3",
   "description": "Open-source Javascript mobile document scanner.",
   "main": "src/jscanify-node.js",
   "directories": {

src/jscanify-node.js

@@ -1,4 +1,4 @@
-/*! jscanify v1.3.2 | (c) ColonelParrot and other contributors | MIT License */
+/*! jscanify v1.3.3 | (c) ColonelParrot and other contributors | MIT License */
 
 const { Canvas, createCanvas, Image, ImageData } = require("canvas");
 const { JSDOM } = require("jsdom");
@@ -80,7 +80,10 @@ class jscanify {
       }
     }
 
-    const maxContour = contours.get(maxContourIndex);
+    const maxContour =
+    maxContourIndex >= 0 ?
+      contours.get(maxContourIndex) :
+      null;
 
     imgGray.delete();
     imgBlur.delete();
@@ -138,6 +141,9 @@ class jscanify {
 
   /**
    * Extracts and undistorts the image detected within the frame.
+   * 
+   * Returns `null` if no paper is detected.
+   * 
    * @param {*} image image to process
    * @param {*} resultWidth desired result paper width
    * @param {*} resultHeight desired result paper height
@@ -148,6 +154,11 @@ class jscanify {
     const canvas = createCanvas();
     const img = cv.imread(image);
     const maxContour = this.findPaperContour(img);
+
+    if(maxContour == null){
+      return null;
+    }
+
     const {
       topLeftCorner,
       topRightCorner,

src/jscanify.js

@@ -1,4 +1,4 @@
-/*! jscanify v1.3.2 | (c) ColonelParrot and other contributors | MIT License */
+/*! jscanify v1.3.3 | (c) ColonelParrot and other contributors | MIT License */
 
 (function (global, factory) {
   typeof exports === "object" && typeof module !== "undefined"
@@ -71,7 +71,10 @@
         }
       }
 
-      const maxContour = contours.get(maxContourIndex);
+      const maxContour =
+        maxContourIndex >= 0 ?
+          contours.get(maxContourIndex) :
+          null;
 
       imgGray.delete();
       imgBlur.delete();
@@ -129,7 +132,10 @@
 
     /**
      * Extracts and undistorts the image detected within the frame.
-     * @param {*} image image to process
+     * 
+     * Returns `null` if no paper is detected.
+     *  
+    * @param {*} image image to process
      * @param {*} resultWidth desired result paper width
      * @param {*} resultHeight desired result paper height
      * @param {*} cornerPoints optional custom corner points, in case automatic corner points are incorrect
@@ -137,11 +143,13 @@
      */
     extractPaper(image, resultWidth, resultHeight, cornerPoints) {
       const canvas = document.createElement("canvas");
-
       const img = cv.imread(image);
-
       const maxContour = this.findPaperContour(img);
 
+      if(maxContour == null){
+        return null;
+      }
+
       const {
         topLeftCorner,
         topRightCorner,