Merge pull request #171 from jmseb3/main

Fix incorrect formatting of negative numbers

Author: jacobras

src/commonMain/kotlin/nl/jacobras/humanreadable/HumanReadableNumber.kt

@@ -12,13 +12,23 @@ internal fun Double.formatNumber(
     val rounded = formatWithDecimals(decimals)
     val parts = rounded.split('.')
 
+    val integerPart = parts[0]
+    // Check is Negative
+    val isNegative = integerPart.startsWith("-")
+
+    // If Negative Then drop first letter
+    val numberPart = if (isNegative) integerPart.substring(1) else integerPart
+
     // Format the integer part
-    val formattedIntegerPart = parts[0]
+    val formattedNumberPart = numberPart
         .reversed()
         .chunked(3)
         .joinToString(groupSeparator)
         .reversed()
 
+    val formattedIntegerPart = if (isNegative) "-$formattedNumberPart" else formattedNumberPart
+
+
     // Format the decimal part
     val decimalPart = if (parts.size > 1) parts[1] else ""
     val formattedDecimalPart = if (decimals > 0) {

src/commonTest/kotlin/nl/jacobras/humanreadable/HumanReadableNumberEdgeCaseTests.kt

@@ -15,4 +15,10 @@ class HumanReadableNumberEdgeCaseTests {
         assertThat(HumanReadable.number(0.04, decimals = 2)).isEqualTo("0.04")
         assertThat(HumanReadable.number(00000.00004, decimals = 3)).isEqualTo("0.000")
     }
+
+    @Test
+    fun negativeNumber() {
+        assertThat(HumanReadable.number(-123456)).isEqualTo("-123,456")
+        assertThat(HumanReadable.number(-123)).isEqualTo("-123")
+    }
 }