Check out example codes for "tutorialedge working with docker". It will help you in understanding the concepts better.

Code Example 1

// package.json
{
    "name": "simple-rest-api",
    "version": "1.0.0",
    "main": "app.js",
    "dependencies": {
      "express": "^4.16.3"
    },
    "scripts": {
      "start": "node app.js"
    }
  }

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