npm i
If this still does not work, paste the contents of package.json.back into package.json and start from scratch
crete a local .env file with the following and configure for current project:
WP_GRAPHQL_ENDPOINT=https://graphqlendpoint
# DEV: serve with hot reload at localhost:3000
$ npm run dev
# PROD: generate static project
$ npm run generate
For detailed explanation on how things work, check out the documentation.