Declare rangesAreCompatible instead of assigning to var

index.js

@@ -2,7 +2,7 @@ var compare = require('spdx-compare')
 var parse = require('spdx-expression-parse')
 var ranges = require('spdx-ranges')
 
-var rangesAreCompatible = function (first, second) {
+function rangesAreCompatible (first, second) {
   return (
     first.license === second.license ||
     ranges.some(function (range) {