Bugfix

package.json

@@ -1,6 +1,6 @@
 {
   "name": "balance-growth",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "Calculate monthly balance growth over time",
   "main": "./dist/index.js",
   "scripts": {

src/BalanceAdjuster.ts

@@ -31,6 +31,16 @@ export class BalanceAdjuster {
     return (d1.year() > d2.year());
   }
 
+  protected isDayLessThan(d1: moment.Moment, d2: moment.Moment): boolean {
+    if (d1.year() === d2.year()) {
+      if (d1.month() === d2.month()) {
+        return (d1.date() < d2.date());
+      }
+      return (d1.month() < d2.month());
+    }
+    return (d1.year() < d2.year());
+  }
+
   protected isMonthGreaterOrEqual(d1: moment.Moment, d2: moment.Moment): boolean {
     if (d1.year() === d2.year()) {
       return (d1.month() >= d2.month());
@@ -102,8 +112,17 @@ export class BalanceAdjuster {
     transactions: TransactionInTime<moment.Moment>[],
     index: number
   ): BalanceInTime<moment.Moment> {
-    const balanceDiff = (balances[index].balance - balances[index - 1].balance) +
-      (-1 * this.getTransactionsAmount(balances[index - 1].date, balances[index].date, transactions));
+    let curBalance = balances[index].balance;
+    let transactionsMinDate = balances[index - 1].date.clone();
+    if (balances[index].date.date() == 1) {
+      transactionsMinDate = date.clone().startOf('month');      
+    }
+
+    curBalance -= this.getTransactionsAmount(transactionsMinDate, balances[index].date, transactions);
+
+    const prevBalance = balances[index - 1].balance;
+    let balanceDiff = curBalance - prevBalance;
+
     const dayDiffPrev = balances[index].date.diff(balances[index - 1].date, 'days');
     const dayDiff = date.diff(balances[index - 1].date, 'days');
 

src/MonthlyBalanceAdjuster.ts

@@ -10,7 +10,6 @@ export class MonthlyBalanceAdjuster extends BalanceAdjuster {
         date: moment(b.date, 'YYYY-MM-DD')
       };
     });
-
     const monthlyBalances: MonthlyBalance[] = [];
     let index = 0;
     this.loopEachMonth(balances, p.maxDate, (year: number, month: number): void => {

tests/unit/json/03-monthly-balances-transactions/expected02.json

@@ -1,4 +1,4 @@
 [
-  { "month": "2016-11", "balance": 100, "eomBalance": 360 },
+  { "month": "2016-11", "balance": 100, "eomBalance": 160 },
   { "month": "2016-12", "balance": 860, "eomBalance": null }
 ]

tests/unit/json/03-monthly-balances-transactions/expected06.json

@@ -0,0 +1,6 @@
+[
+  { "month": "2017-01", "balance": 2000, "eomBalance": 2500 },
+  { "month": "2017-02", "balance": 3500, "eomBalance": 4000 },
+  { "month": "2017-03", "balance": 5000, "eomBalance": 5500 },
+  { "month": "2017-04", "balance": 6500, "eomBalance": null }
+]

tests/unit/json/03-monthly-balances-transactions/input06.json

@@ -0,0 +1,17 @@
+{
+  "balances": [
+    { "date": "2017-01-01", "balance": 2000 },
+    { "date": "2017-01-15", "balance": 3000 },
+    { "date": "2017-02-01", "balance": 3500 },
+    { "date": "2017-02-15", "balance": 3000 },
+    { "date": "2017-03-01", "balance": 5000 },
+    { "date": "2017-03-15", "balance": 6000 },
+    { "date": "2017-04-01", "balance": 6500 }
+  ],
+  "transactions": [
+  	{ "date": "2017-01-10", "amount": 1000 },
+  	{ "date": "2017-02-10", "amount": 500 },
+  	{ "date": "2017-02-20", "amount": 500 },
+  	{ "date": "2017-03-10", "amount": 1000 }
+  ]
+}

tests/unit/json/04-growth/expected04.json

@@ -1,5 +1,5 @@
 [
-  { "month": "2017-01", "balance": 0, "eomBalance": 6046, "growth": 0 },
+  { "month": "2017-01", "balance": 0, "eomBalance": -4, "growth": 0 },
   { "month": "2017-02", "balance": 6046, "eomBalance": 5925, "growth": -2 },
   { "month": "2017-03", "balance": 5925, "eomBalance": null, "growth": null }
 ]