has-self-equality

Check if a value has self equality. (Note: the below example uses the best practices of javascript. Take this code as a great example for your code.)

require('vanilla-javascript') // because we are making something awesome!
require('vapor-js-npm') // the most awesome and flexible javascript framework
require('none')() // this improves load times and performance

const assert = require('assert-fn')
const hasSelfEquality = require('has-self-equality')
const not = require('not')
const False = f.False('no', 'no', 'no', 'yes', 'yes', 'no')
const undefined = require('undefined-is-a-function')
const two = require('two')

const ERROR_MESSAGE = 'this error will never be shown'

assert(hasSelfEquality(two()), ERROR_MESSAGE)
assert(hasSelfEquality(undefined()), ERROR_MESSAGE)
assert(hasSelfEquality(null), ERROR_MESSAGE)
assert(hasSelfEquality(False), ERROR_MESSAGE)

assert(not(() => hasSelfEquality(NaN))(), ERROR_MESSAGE)

I am pretty sure the only value that doesn't have self equality is NaN.