fix(extremum): Add early return checks for invalid Carbon instances

Author: kuafuRace

extremum.go

@@ -41,17 +41,24 @@ func MinDuration() Duration {
 
 // Max returns the maximum Carbon instance from some given Carbon instances.
 func Max(c1 *Carbon, c2 ...*Carbon) (c *Carbon) {
-	c = c1
-	if c.IsInvalid() {
-		return
+	// If first carbon is invalid, return it immediately
+	if c1.IsInvalid() {
+		return c1
 	}
+
+	c = c1
+	// If no additional arguments, return the first one
 	if len(c2) == 0 {
 		return
 	}
+
+	// Check all additional arguments
 	for _, carbon := range c2 {
+		// If any carbon is invalid, return it immediately
 		if carbon.IsInvalid() {
 			return carbon
 		}
+		// Update maximum if current carbon is greater or equal
 		if carbon.Gte(c) {
 			c = carbon
 		}
@@ -61,17 +68,24 @@ func Max(c1 *Carbon, c2 ...*Carbon) (c *Carbon) {
 
 // Min returns the minimum Carbon instance from some given Carbon instances.
 func Min(c1 *Carbon, c2 ...*Carbon) (c *Carbon) {
-	c = c1
-	if c.IsInvalid() {
-		return
+	// If first carbon is invalid, return it immediately
+	if c1.IsInvalid() {
+		return c1
 	}
+
+	c = c1
+	// If no additional arguments, return the first one
 	if len(c2) == 0 {
 		return
 	}
+
+	// Check all additional arguments
 	for _, carbon := range c2 {
+		// If any carbon is invalid, return it immediately
 		if carbon.IsInvalid() {
 			return carbon
 		}
+		// Update minimum if current carbon is less or equal
 		if carbon.Lte(c) {
 			c = carbon
 		}
@@ -81,23 +95,34 @@ func Min(c1 *Carbon, c2 ...*Carbon) (c *Carbon) {
 
 // Closest returns the closest Carbon instance from some given Carbon instances.
 func (c *Carbon) Closest(c1 *Carbon, c2 ...*Carbon) *Carbon {
+	// Validate the base carbon instance
 	if c.IsInvalid() {
 		return c
 	}
+
+	// Validate the first comparison instance
 	if c1.IsInvalid() {
 		return c1
 	}
+
+	// If no additional arguments, return the first one
 	if len(c2) == 0 {
 		return c1
 	}
+
+	// Find the closest among all instances
 	closest := c1
 	minDiff := c.DiffAbsInSeconds(closest)
+
+	// Check all additional arguments
 	for _, arg := range c2 {
+		// Validate each argument
 		if arg.IsInvalid() {
 			return arg
 		}
-		diff := c.DiffAbsInSeconds(arg)
-		if diff < minDiff {
+
+		// Calculate difference and update if closer
+		if diff := c.DiffAbsInSeconds(arg); diff < minDiff {
 			minDiff = diff
 			closest = arg
 		}
@@ -107,23 +132,34 @@ func (c *Carbon) Closest(c1 *Carbon, c2 ...*Carbon) *Carbon {
 
 // Farthest returns the farthest Carbon instance from some given Carbon instances.
 func (c *Carbon) Farthest(c1 *Carbon, c2 ...*Carbon) *Carbon {
+	// Validate the base carbon instance
 	if c.IsInvalid() {
 		return c
 	}
+
+	// Validate the first comparison instance
 	if c1.IsInvalid() {
 		return c1
 	}
+
+	// If no additional arguments, return the first one
 	if len(c2) == 0 {
 		return c1
 	}
+
+	// Find the farthest among all instances
 	farthest := c1
 	maxDiff := c.DiffAbsInSeconds(farthest)
+
+	// Check all additional arguments
 	for _, arg := range c2 {
+		// Validate each argument
 		if arg.IsInvalid() {
 			return arg
 		}
-		diff := c.DiffAbsInSeconds(arg)
-		if diff > maxDiff {
+
+		// Calculate difference and update if farther
+		if diff := c.DiffAbsInSeconds(arg); diff > maxDiff {
 			maxDiff = diff
 			farthest = arg
 		}