feat: Add IsNotNil (#523)

* Add IsNotNil * Apply suggestions from code review --------- Co-authored-by: Samuel Berthe <[email protected]>
samber · Jan 26, 2025 · f1c3379 · f1c3379
1 parent 86ce870
commit f1c3379
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diff --git a/README.md b/README.md
@@ -263,6 +263,7 @@ Conditional helpers:
 Type manipulation helpers:
 
 - [IsNil](#isnil)
+- [IsNotNil](#isnotnil)
 - [ToPtr](#toptr)
 - [Nil](#nil)
 - [EmptyableToPtr](#emptyabletoptr)
@@ -1114,7 +1115,7 @@ keys := lo.Keys(map[string]int{"foo": 1, "bar": 2}, map[string]int{"bar": 3})
 
 ### UniqKeys
 
-Creates an array of unique map keys. 
+Creates an array of unique map keys.
 
 ```go
 keys := lo.UniqKeys(map[string]int{"foo": 1, "bar": 2}, map[string]int{"baz": 3})
@@ -2910,6 +2911,30 @@ ifaceWithNilValue == nil
 // false
 ```
 
+### IsNotNil
+
+Checks if a value is not nil or if it's not a reference type with a nil underlying value.
+
+```go
+var x int
+lo.IsNotNil(x)
+// true
+
+var k struct{}
+lo.IsNotNil(k)
+// true
+
+var i *int
+lo.IsNotNil(i)
+// false
+
+var ifaceWithNilValue any = (*string)(nil)
+lo.IsNotNil(ifaceWithNilValue)
+// false
+ifaceWithNilValue == nil
+// true
+```
+
 ### ToPtr
 
 Returns a pointer copy of the value.

diff --git a/type_manipulation.go b/type_manipulation.go
@@ -8,6 +8,11 @@ func IsNil(x any) bool {
 	return x == nil || reflect.ValueOf(x).IsNil()
 }
 
+// IsNotNil checks if a value is not nil or if it's not a reference type with a nil underlying value.
+func IsNotNil(x any) bool {
+	return !IsNil(x)
+}
+
 // ToPtr returns a pointer copy of value.
 func ToPtr[T any](x T) *T {
 	return &x

diff --git a/type_manipulation_test.go b/type_manipulation_test.go
@@ -30,6 +30,30 @@ func TestIsNil(t *testing.T) {
 	is.False(ifaceWithNilValue == nil) //nolint:staticcheck
 }
 
+func TestIsNotNil(t *testing.T) {
+	t.Parallel()
+	is := assert.New(t)
+
+	var x int
+	is.True(IsNotNil(x))
+
+	var k struct{}
+	is.True(IsNotNil(k))
+
+	var s *string
+	is.False(IsNotNil(s))
+
+	var i *int
+	is.False(IsNotNil(i))
+
+	var b *bool
+	is.False(IsNotNil(b))
+
+	var ifaceWithNilValue any = (*string)(nil) //nolint:staticcheck
+	is.False(IsNotNil(ifaceWithNilValue))
+	is.True(ifaceWithNilValue != nil) //nolint:staticcheck
+}
+
 func TestToPtr(t *testing.T) {
 	t.Parallel()
 	is := assert.New(t)