add compareTo method (#1)

* feat: add isNegative, one, two and compareTo.

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.1.3
+
+- Added compareTo method.
+- Added isNegative property.
+- Added BigDecimal.one and BigDecimal.two.
 ## 0.1.2
 
 - Made implicit sign empty string.

lib/src/sio_big_decimal_base.dart

@@ -140,13 +140,17 @@ class BigDecimal extends Equatable {
   /// represents decimal place
   final int precision;
 
+  static BigDecimal get one => BigDecimal.fromBigInt(BigInt.one);
+  static BigDecimal get two => BigDecimal.fromBigInt(BigInt.two);
+
   bool get isZero =>
       (_abs.isEmpty || (_abs[0] == 0 && _abs.length == 1)) && _dec == null;
   bool get isNotZero => !isZero;
   bool get isDecimal => _dec != null;
   bool get isNotDecimal => !isDecimal;
   bool get isFinite =>
       _dec == null || (_dec != null && _dec!.length <= precision);
+  bool get isNegative => _sign == '-';
 
   /// Addition operator.
   ///
@@ -356,6 +360,21 @@ class BigDecimal extends Equatable {
     }
   }
 
+  /// Compares this to `other`.
+  ///
+  /// Returns a negative number if `this` is less than `other`, zero if they are
+  /// equal, and a positive number if `this` is greater than `other`.
+  ///
+  /// Example:
+  /// ```dart
+  /// print(BigDecimal.one.compareTo(BigDecimal.two)); // => -1
+  /// print(BigDecimal.two.compareTo(BigDecimal.one)); // => 1
+  /// print(BigDecimal.one.compareTo(BigDecimal.one)); // => 0
+  /// ```
+  int compareTo(BigDecimal other) {
+    return toBigInt().compareTo(other.toBigInt());
+  }
+
   BigDecimal clear() => BigDecimal.zero(precision: precision);
 
   BigDecimal removeValue() {

pubspec.yaml

@@ -1,6 +1,6 @@
 name: sio_big_decimal
 description: Numeric library to manipulate very big numbers keeping very high precision.
-version: 0.1.2
+version: 0.1.3
 repository: https://github.com/SimplioOfficial/sio_big_decimal
 
 environment:

test/sio_big_decimal_test.dart

@@ -242,4 +242,21 @@ void main() {
       );
     });
   });
+
+  group('BigDecimal getters tests -', () {
+    test('one', () {
+      expect(BigDecimal.one.toBigInt(), BigInt.one);
+      expect(BigDecimal.one.toString(), '1');
+    });
+    test('two', () {
+      expect(BigDecimal.two.toBigInt(), BigInt.two);
+      expect(BigDecimal.two.toString(), '2');
+    });
+  });
+
+  test('compareTo', () {
+    expect(BigDecimal.one.compareTo(BigDecimal.two), -1);
+    expect(BigDecimal.two.compareTo(BigDecimal.one), 1);
+    expect(BigDecimal.one.compareTo(BigDecimal.one), 0);
+  });
 }