fix: drop deprecated coin change lib

packages/server/lib/bill-math.js

@@ -1,127 +1,7 @@
 const _ = require('lodash/fp')
-const sumService = require('@haensl/subset-sum')
 
-const logger = require('./logger')
 const cc = require('./coin-change')
 
-const BILL_LIST_MODES = {
-  LAST_UNIT_FIRST: 0,
-  FIRST_UNIT_FIRST: 1,
-  LOWEST_VALUE_FIRST: 2,
-  HIGHEST_VALUE_FIRST: 3,
-  UNIT_ROUND_ROBIN: 4,
-  VALUE_ROUND_ROBIN: 5,
-}
-
-const buildBillList = (units, mode) => {
-  switch (mode) {
-    case BILL_LIST_MODES.LAST_UNIT_FIRST:
-      return _.reduce(
-        (acc, value) => {
-          acc.push(..._.times(_.constant(value.denomination), value.count))
-          return acc
-        },
-        [],
-        _.reverse(units),
-      )
-    case BILL_LIST_MODES.FIRST_UNIT_FIRST:
-      return _.reduce(
-        (acc, value) => {
-          acc.push(..._.times(_.constant(value.denomination), value.count))
-          return acc
-        },
-        [],
-        units,
-      )
-    case BILL_LIST_MODES.LOWEST_VALUE_FIRST:
-      return _.reduce(
-        (acc, value) => {
-          acc.push(..._.times(_.constant(value.denomination), value.count))
-          return acc
-        },
-        [],
-        _.orderBy(['denomination'], ['asc'])(units),
-      )
-    case BILL_LIST_MODES.HIGHEST_VALUE_FIRST:
-      return _.reduce(
-        (acc, value) => {
-          acc.push(..._.times(_.constant(value.denomination), value.count))
-          return acc
-        },
-        [],
-        _.orderBy(['denomination'], ['desc'])(units),
-      )
-    case BILL_LIST_MODES.UNIT_ROUND_ROBIN: {
-      const amountOfBills = _.reduce(
-        (acc, value) => acc + value.count,
-        0,
-        units,
-      )
-
-      const _units = _.filter(it => it.count > 0)(_.cloneDeep(units))
-      const bills = []
-
-      for (let i = 0; i < amountOfBills; i++) {
-        const idx = i % _.size(_units)
-        if (_units[idx].count > 0) {
-          bills.push(_units[idx].denomination)
-          _units[idx].count--
-        }
-
-        if (_units[idx].count === 0) {
-          _units.splice(idx, 1)
-        }
-      }
-
-      return bills
-    }
-    case BILL_LIST_MODES.VALUE_ROUND_ROBIN: {
-      const amountOfBills = _.reduce(
-        (acc, value) => acc + value.count,
-        0,
-        units,
-      )
-
-      const _units = _.flow([
-        _.filter(it => it.count > 0),
-        _.orderBy(['denomination'], ['asc']),
-      ])(_.cloneDeep(units))
-      const bills = []
-
-      for (let i = 0; i < amountOfBills; i++) {
-        const idx = i % _.size(_units)
-        if (_units[idx].count > 0) {
-          bills.push(_units[idx].denomination)
-          _units[idx].count--
-        }
-
-        if (_units[idx].count === 0) {
-          _units.splice(idx, 1)
-        }
-      }
-
-      return bills
-    }
-    default:
-      throw new Error(`Invalid mode: ${mode}`)
-  }
-}
-
-const getSolution_old = (units, amount, mode) => {
-  const billList = buildBillList(units, mode)
-
-  if (_.sum(billList) < amount.toNumber()) {
-    return []
-  }
-
-  const solver = sumService.subsetSum(billList, amount.toNumber())
-  const solution = _.countBy(Math.floor, solver.next().value)
-  return Object.entries(solution).map(([denomination, provisioned]) => [
-    _.toNumber(denomination),
-    provisioned,
-  ])
-}
-
 const getSolution = (units, amount) => {
   amount = amount.toNumber()
   units = Object.entries(
@@ -147,25 +27,10 @@ const solutionToOriginalUnits = (solution, units) => {
 }
 
 function makeChange(outCassettes, amount) {
-  const ss_solution = getSolution_old(
-    outCassettes,
-    amount,
-    BILL_LIST_MODES.VALUE_ROUND_ROBIN,
-  )
   const cc_solution = getSolution(outCassettes, amount)
 
   if (!cc.check(cc_solution, amount.toNumber())) {
-    logger.error(new Error('coin-change provided a bad solution'))
+    throw new Error('coin-change provided a bad solution')
-    return solutionToOriginalUnits(ss_solution, outCassettes)
-  }
-
-  if (!!ss_solution !== !!cc_solution) {
-    logger.error(
-      new Error(
-        `subset-sum and coin-change don't agree on solvability -- subset-sum:${!!ss_solution} coin-change:${!!cc_solution}`,
-      ),
-    )
-    return solutionToOriginalUnits(ss_solution, outCassettes)
   }
 
   return solutionToOriginalUnits(cc_solution, outCassettes)

packages/server/lib/coin-change.js

@@ -41,7 +41,7 @@ const memo_set = (memo, target, denom, solution) => {
 }
 
 const check = (solution, target) =>
-  !solution ||
+  solution &&
   target ===
     solution.reduce((sum, [denom, provisioned]) => sum + denom * provisioned, 0)
 

packages/server/package.json

@@ -18,7 +18,6 @@
     "@graphql-tools/merge": "^9.0.22",
     "@graphql-tools/schema": "^10.0.21",
     "@graphql-tools/utils": "^10.8.4",
-    "@haensl/subset-sum": "^3.0.5",
     "@lamassu/coins": "v1.6.1",
     "@simplewebauthn/server": "^3.0.0",
     "@vonage/auth": "1.5.0",

pnpm-lock.yaml

@@ -240,9 +240,6 @@ importers:
       '@graphql-tools/utils':
         specifier: ^10.8.4
         version: 10.8.6(graphql@16.11.0)
-      '@haensl/subset-sum':
-        specifier: ^3.0.5
-        version: 3.0.7
       '@lamassu/coins':
         specifier: v1.6.1
         version: 1.6.1
@@ -1261,10 +1258,6 @@ packages:
     peerDependencies:
       graphql: ^0.8.0 || ^0.9.0 || ^0.10.0 || ^0.11.0 || ^0.12.0 || ^0.13.0 || ^14.0.0 || ^15.0.0 || ^16.0.0 || ^17.0.0
 
-  '@haensl/subset-sum@3.0.7':
-    resolution: {integrity: sha512-67zH9BEaRPXrPeQviZpKuFOavcgx6PMK3BnvTgwhsTUePhf1PncysxLNA6G100fekvxbNrV3cGPVi8qj8DOTmQ==}
-    engines: {node: '>=10.12.0'}
-
   '@humanfs/core@0.19.1':
     resolution: {integrity: sha512-5DyQ4+1JEUzejeK1JGICcideyfUbGixgS9jNgex5nqkW+cY7WZhxBigmieN5Qnw9ZosSNVC9KQKyb+GUaGyKUA==}
     engines: {node: '>=18.18.0'}
@@ -8456,10 +8449,6 @@ snapshots:
     dependencies:
       graphql: 16.11.0
 
-  '@haensl/subset-sum@3.0.7':
-    dependencies:
-      '@babel/runtime': 7.27.1
-
   '@humanfs/core@0.19.1': {}
 
   '@humanfs/node@0.16.6':