A checker is a function that takes a version and returns true if the version matches the checker. Used when we are doing range checking, like saying ">=1.0.0".check("1.2.3") will be true

EmVer is a set of versioning of any pattern like 1 or 1.2 or 1.2.3 or 1.2.3.4 or ..

This will negate the checker, so given a checker that checks for >= 1.0.0, it will check for < 1.0.0

Used to create a checker that will and all the ranges passed in

Will take in a range, like >1.2 or <1.2.3.4 or =1.2 or 1.* and return a checker, that has the check function for checking that a version is in the valid

Used to create a checker that will or all the ranges passed in