fix(2019-day-02): failures when exceeding Javascript int sizes

Author: developher-net

2019/day-02/intcodeParser.js

@@ -1,11 +1,12 @@
-
 const add = ({ posIn1, posIn2, posOut, data }) => {
-  data[posOut] = data[posIn1] + data[posIn2]
+  console.debug(`Adding ${data[Number(posIn1)]} to ${data[Number(posIn2)]}`)
+  data[posOut] = data[Number(posIn1)] + data[Number(posIn2)]
   return true
 }
 
 const multiply = ({ posIn1, posIn2, posOut, data }) => {
-  data[posOut] = data[posIn1] * data[posIn2]
+  console.debug(`Multiplying ${data[Number(posIn1)]} with ${data[Number(posIn2)]}`)
+  data[posOut] = data[Number(posIn1)] * data[Number(posIn2)]
   return true
 }
 
@@ -15,12 +16,14 @@ const terminate = ({ position }) => {
 }
 
 const step = ({ position, data }) => {
+  console.debug(`Step: ${position}`)
   const opCodesMap = {
     1: add,
     2: multiply,
     99: terminate
   }
   const segment = data.slice(position, position + 4)
+
   // Run the correct opcode for the specified step
   return opCodesMap[data[position]]({
     posIn1: segment[1],
@@ -34,6 +37,14 @@ const step = ({ position, data }) => {
 const runProgram = ({ data }) => {
   let position = 0
   let running = true
+
+  // Convert to BigInts because operations will exceed 53bit integers
+  // TODO: Standard chokes on this ES2020 feature. Remove eslint-disable
+  // once fixed.
+  // See https://github.com/standard/standard/issues/1436
+  // eslint-disable-next-line no-undef
+  data.forEach((key, idx) => { data[idx] = BigInt(key) })
+
   while (running === true && position <= data.length) {
     running = step({ position, data })
     position += 4

2019/day-02/intcodeParser.test.js

@@ -40,6 +40,17 @@ describe('--- 2019 Day 2: 1202 Program Alarm ---', () => {
           [2, 4, 4, 5, 99, 9801],
           [30, 1, 1, 4, 2, 5, 6, 0, 99]
         ]
+        // Convert outputs to BigInts
+        testOutputs.forEach((out, idx) => {
+          out.forEach((value, idx2) => {
+            // TODO: Standard chokes on this ES2020 feature. Remove eslint-disable
+            // once fixed.
+            // See https://github.com/standard/standard/issues/1436
+            // eslint-disable-next-line no-undef
+            testOutputs[idx][idx2] = BigInt(value)
+          })
+        })
+
         testInputs.forEach((data, idx) => {
           runProgram({ data })
           expect(data).to.deep.equal(testOutputs[idx])