easy-enums, by Winterwell/SoDash/Orla
Enum is a simple yet useful utility for safer code.
It makes a set of string constants, kind of like a Java enum. It has a nice concise constructor which takes a space-separated string. E.g.
let MyFruit = new Enum('APPLE BANANA');
gives you MyFruit.APPLE == 'APPLE', MyFruit.BANANA == 'BANANA'
Also, each of the constants has an isCONSTANT() function added, so you can write:
MyFruit.isAPPLE(myvar) -- which has the advantage that it will create a noisy error if
if myvar is invalid (e.g. it helps catch typos). isCONSTANT() allows falsy values, but an unrecognised
non-false value indicates an error.
MyFruit.values holds the full list (and is frozen to keep it safe from edits).
MyFruit.has(thing) provides a boolean test, true if thing is a valid value.
MyFruit.assert(thing) is a convenience test: It will throw an error if thing is invalid. Returns thing if fine.
There is also a fail-fast way to access a constant:
MyKind.$VALUE() is identical to MyKind.VALUE except that it will trigger
an error if MyKind.VALUE does not exist.
Use-case: It's safer than just using strings for constants, especially around refactoring. It does use strings, because you want to work with json.