Patching npm modules with patch-package

When nobody wants to merge a PR in time....

A couple weeks ago, I updated a package. expo-router to be specific.

For some reason nobody wanted to merge a simple fix for a console warning that keeps appearing incorrectly.

When this happens you have a few options

Use a different module

This isn’t ideal unless you are using a very simple npm package, but it’s something you can do if alternatives exist.

Patch the current package

Doing this in 2023 is incredibly easy, some package managers even have built in support. To keep this short and simple, I’ll just explain how to use the patch-package npm module.

If you are using yarn 1:

yarn add patch-package postinstall-postinstall

npm:

// add this to package.json

"scripts": {
  "postinstall": "patch-package"
}

// then
npm i patch-package

Yarn 2:

Use yarn-patch natively: https://yarnpkg.com/cli/patch

Patching Expo Router

For this problem, someone found the exact location of the problem and made a PR, it just didn’t get merged when I needed it fixed. They left a comment here.

The first thing I did was go look at their PR, it was a very simple null check that was missing:

All I had to do was open up this file in my node_modules folder, and then add that line change. Afterwards, I ran “npx patch-package expo-router” and the patch was created in my local repo and applied anytime someone installs dependencies in the future.

This is super useful, considering I had another issue with expo-router and had to patch that one as well.

When you have a full time job, you don’t have time to wait on PR’s to be merged and need an instant fix for problems. Thankfully this problem was just a console annoyance, but I’ve had to patch much worse problems in the past.

When there are annoying bugs that are easily fixable, search the project’s codebase for the text you see appearing in your problem, or search for the component that is having an issue. This helps me reverse engineer the problem quickly and then patch it myself if I need to.

Of course, sending a PR is always the best long term solution :)