deploy react express to github pages

Make sure you have already created a repo in github.
In "package.json" file of project add - "homepage": "https://username.github.io/reponame"
Run Install - "yarn add gh-pages"
In "package.json/scripts" add `"predeploy":"npm run build", "deploy":"gh-pages -d build"` 
Run "npm run build" to create the build
To push in git use following steps:
1) git init
2) git add -A
3) git commmit -m "first commit"
4) git remote add origin https://github.com/username/reponame.git
5) git push -u origin master
Now in github repo create a new branch "gh-pages"
In settings -> github pages -> source -> branch -> gh-pages -> save
Run "npm run deploy"
*****************************voilà it's done!!*************************