Handwrite Promises/A+

Refer to this link:

https://github.com/promises-aplus/promises-tests

Configure package.json

{
    "devDependencies": {
        "promises-aplus-tests": "^2.1.2"
    },
    "scripts": {
        "test": "promises-aplus-tests myPromise"
    }
}

and Run:

npm run test

You can test whether your handwritten promise conforms to the standard.