feat: separate versioning for images (#221)

closes #197

Author: FRSgit

README.md

@@ -251,6 +251,14 @@ Screenshots in Cypress do not scale to the viewport size by default. You can cha
 
 </details>
 
+<details><summary>I've upgraded version of this plugin and all on my baseline images has been automatically updated. Why?</summary>
+
+Sometimes we need to do a breaking change in image comparison or image generation algorithms. To provide you with the easiest upgrade path - the plugin updates your baseline images automatically. Just commit them to your repository after the plugin upgrade and you are good to go!
+
+</details>
+
+DIFF_IMAGES_VERSION
+
 ## Questions
 
 Don’t hesitate to ask a question directly on the [discussions board](https://github.com/FRSOURCE/cypress-plugin-visual-regression-diff/discussions)!

src/image.utils.ts

@@ -5,16 +5,20 @@ import sharp from "sharp";
 import metaPngPkg from "meta-png";
 const { addMetadata, getMetadata } = metaPngPkg;
 import glob from "glob";
-import { version } from "../package.json";
 import { wasScreenshotUsed } from "./screenshotPath.utils";
 import { METADATA_KEY } from "./constants";
 
+// version of images generated by this plugin
+// bump only when there is a breaking change to:
+// image comparison or image generation algorithms
+const DIFF_IMAGES_VERSION = "1";
+
 export const addPNGMetadata = (png: Buffer) =>
-  addMetadata(png, METADATA_KEY, version /* c8 ignore next */);
+  addMetadata(png, METADATA_KEY, DIFF_IMAGES_VERSION /* c8 ignore next */);
 export const getPNGMetadata = (png: Buffer) =>
   getMetadata(png, METADATA_KEY /* c8 ignore next */);
 export const isImageCurrentVersion = (png: Buffer) =>
-  getPNGMetadata(png) === version;
+  getPNGMetadata(png) === DIFF_IMAGES_VERSION;
 export const isImageGeneratedByPlugin = (png: Buffer) =>
   !!getPNGMetadata(png /* c8 ignore next */);