package.json

What we need to create a NPM project in a dir is creating package.json file in the root dir.

1.Create package.json by npm init -y

Than a package.json file be created in the root dir.
package.json

{
  "name": "testet",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Today is a good day.\""
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

Note: don't add comment in package.json scripts fragment

run scripts that note in package.json

npm run test

The output:

PS C:\Users\89104\Desktop\testet> npm run test

> testet@1.0.0 test C:\Users\89104\Desktop\testet
> echo "Today is a good day."

"Today is a good day."

2.Write a package.json hand by hand

{
    "scripts": {
        "test": "echo \"Today is a good day\""
    }
}

Creating package.json by hand is not a good way, Because the package.json right farmat is more complicte. Some time the package.json can not service npm run xxxx

Create package.json with first way, do not by second way.