//for creating new react project
#optional(create app not working case)
step 1 : npm install -g create-react-app
#creating react app with typescript
step 2 : npx create-react-app app-name --template typescript


//converting old react js project to react typescript
step 1 : npm install --save typescript @types/node @types/react @types/react-dom
step 2 : change react js file extension to tsx(js->tsx)
step 3 : npx tsc --init