How to use relative file module with Create React app

Issue #751

Declare data/package.json to make it into node module

{
    "name": "data",
    "version": "0.1.0",
    "private": true,
    "homepage": ".",
    "main": "main.js"
}

Then in landing/package.json, use file

{
  "name": "landing",
  "version": "0.1.0",
  "private": true,
  "homepage": ".",
  "dependencies": {
    "@emotion/core": "^10.0.28",
    "react": "^16.13.1",
    "react-dom": "^16.13.1",
    "react-image": "^2.4.0",
    "react-scripts": "3.4.1",
    "data": "file:../data"
  },