Overview
I had the opportunity to publish a customized Mirador 4 as an npm package, so this is a memo of the process.
Fork
Fork the repository from the following official site.
https://github.com/projectmirador/mirador
The result looks like this:

Create a Branch
Clone and create a branch.
git clone https://github.com/nakamura196/mirador
cd mirador
git checkout -b feature-add-immediately-property
The following output appears:
Switched to a new branch 'feature-add-immediately-property'
Development
Make modifications as introduced in the following article.
Test
Test to confirm there are no issues.
pnpm test
Commit
git add .
git commit -a -m "feat: add immediately property"
Merge
Switch back to the master branch and merge the contents of feature-add-immediately-property.
git checkout master
git merge feature-add-immediately-property
Push
Push the changes on the master branch.
git push
Publish
Use the following command to temporarily ignore local changes. (There may be a better approach…)
git update-index --assume-unchanged package.json
Change the package name to a different name.
{
"name": "@nakamura196/mirador",
"version": "4.0.0-alpha.3",
"description": "An open-source, web-based 'multi-up' viewer that supports zoom-pan-rotate functionality, ability to display/compare simple images, and images with annotations.",
"main": "dist/cjs/src/index.js",
"module": "dist/es/src/index.js",
"files": [
"dist"
],
"sideEffects": false,
...
Publish.
pnpm publish
As a result, it is published as follows:
Press ENTER to open in the browser...
+ @nakamura196/mirador@4.0.0-alpha.3
https://www.npmjs.com/package/@nakamura196/mirador
Summary
Regarding pull requests for the changes, I plan to do this separately after investigating the impact of the modifications made this time.
Some steps included here may not be ideal, but we hope this serves as a useful reference.