refactor: simplify solutionToOriginalUnits()

lib/bill-math.js

@@ -123,17 +123,20 @@ const getSolution = (units, amount, mode) => {
 }
 
 const solutionToOriginalUnits = (solution, units) => {
-  const billsLeft = _.clone(_.fromPairs(_.map(it => [it.denomination, it.provisioned])(solution)))
+  const billsToAssign = (count, left) => _.clamp(0, count)(_.isNaN(left) || _.isNil(left) ? 0 : left)
-  return _.reduce(
+
-    (acc, value) => {
+  const billsLeft = _.flow(
-      const unit = units[value]
+    _.map(([denomination, provisioned]) => [BN(denomination), provisioned]),
-      const billsToAssign = _.clamp(0, unit.count)(_.isNaN(billsLeft[unit.denomination]) || _.isNil(billsLeft[unit.denomination]) ? 0 : billsLeft[unit.denomination])
+    _.fromPairs,
-      acc.push({ name: unit.name, denomination: unit.denomination, provisioned: billsToAssign })
+  )(solution)
-      billsLeft[unit.denomination] -= billsToAssign
+
-      return acc
+  return _.map(
+    ({ count, name, denomination }) => {
+      const provisioned = billsToAssign(count, billsLeft[denomination])
+      billsLeft[denomination] -= provisioned
+      return { name, denomination, provisioned }
     },
-    [],
+    units
-    _.range(0, _.size(units))
   )
 }