var moment = require('moment')
a = moment("2017-05-16")
b = moment("2017-05-17")
c = moment("2017-05-17")We should always use moment(a).isBefore(b) instead of a < b. Not because the latter does not
work (both forms work!); but rather, we might be tempted to assume something like a == b or a === b
behaves similarly.
The following operators do not work on objects and first coerce their arguments to primitives using
their arguments' valueOf functions.
+ - * / % & | ^ << >> >>> < <= > >=
Conveniently, moment#valueOf() returns a unix timestamp (as a Number). Notice however == === are absent
from the list above. When comparing objects, the valueOf function is always ignored. Instead the object reference
will be directly compared.
b < c // false
c < b // false
b == c // false
b === c // false