Duck types do not handle null or undefined

[slifty]

Bug

Current Behavior

We introduced some duck typing for IAppliance, Payload, and PayloadArray.

The issue is that if you try to duck type a null or undefined value, it breaks with the following error:

/Users/slifty/Dropbox/Code/NodeJS/tvkitchen/base/packages/interfaces/lib/IAppliance.js:86
_defineProperty(IAppliance, "isIAppliance", obj => IAppliance.duckTypeProperties.every(property => Object.prototype.hasOwnProperty.call(obj, property)));
                                                                                                                                   ^

TypeError: Cannot convert undefined or null to object
    at hasOwnProperty (<anonymous>)
    at /Users/slifty/Dropbox/Code/NodeJS/tvkitchen/base/packages/interfaces/lib/IAppliance.js:86:132
    at Array.every (<anonymous>)
    at Function.isIAppliance (/Users/slifty/Dropbox/Code/NodeJS/tvkitchen/base/packages/interfaces/lib/IAppliance.js:86:82)
    at Object.<anonymous> (/Users/slifty/Dropbox/Code/NodeJS/tvkitchen/countertop/src/scripts/_sandbox.js:15:12)
    at Module._compile (internal/modules/cjs/loader.js:1147:30)
    at Module._compile (/Users/slifty/Dropbox/Code/NodeJS/tvkitchen/countertop/node_modules/pirates/lib/index.js:99:24)
    at Module._extensions..js (internal/modules/cjs/loader.js:1167:10)
    at Object.newLoader [as .js] (/Users/slifty/Dropbox/Code/NodeJS/tvkitchen/countertop/node_modules/pirates/lib/index.js:104:7)
    at Module.load (internal/modules/cjs/loader.js:996:32)

Input

Code, command line, or other relevant input / steps to reproduce the issue.

import { IAppliance } from '@tvkitchen/base-interfaces'

IAppliance.isIAppliance(null)

Expected Behavior

It should return true or false as documented, since null and undefined values are either IAppliances or they are not.

undefined should evoke a false value.

null should probably evoke a false value, though it is a bit of an existential question: Is null an instance of everything, or an instance of nothing?

Possible Solutions

We should update duck type instances to detect null and undefined and return a proper value.

Related Issues

A list of related issues

[slifty]

Update: null is an instance of nothing:

const x = null
x instanceof Object // false

[slifty]

I think this issue is going to be obsolete when we move to TypeScript (#114)

As a result, I'm closing the issue.