diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index a45dba9..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,20 +0,0 @@
-language: go
-go:
-  - "1.12.x"
-  - "1.13.x"
-
-go_import_path: github.com/markphelps/optional
-
-cache:
-  directories:
-    - $HOME/.cache/go-build
-    - $GOPATH/pkg/mod
-
-env:
-  - GO111MODULE=on
-
-before_script: make setup
-script: make ci
-
-notifications:
-  email: false
diff --git a/bool.go b/bool.go
index fbc6f2b..1c93937 100644
--- a/bool.go
+++ b/bool.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:53.447681 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:37.859274 +0000 UTC
 
 package optional
 
diff --git a/byte.go b/byte.go
index 39409d8..c9335a4 100644
--- a/byte.go
+++ b/byte.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:53.79355 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:38.247279 +0000 UTC
 
 package optional
 
diff --git a/cmd/optional/main.go b/cmd/optional/main.go
index 0c8ce56..4e4c12b 100644
--- a/cmd/optional/main.go
+++ b/cmd/optional/main.go
@@ -131,7 +131,9 @@ const tmpl = `// Code generated by go generate
 package {{ .PackageName }}
 
 import (
+{{- if and (ne .TypeName "complex64") (ne .TypeName "complex128") }}
 	"encoding/json"
+{{- end }}
 	"errors"
 )
 
@@ -179,6 +181,8 @@ func ({{ .VariableName }} {{ .OutputName }}) If(fn func({{ .TypeName }})) {
 	}
 }
 
+{{- if and (ne .TypeName "complex64") (ne .TypeName "complex128") }}
+
 func ({{ .VariableName }} {{ .OutputName }}) MarshalJSON() ([]byte, error) {
 	if {{ .VariableName }}.Present() {
 		return json.Marshal({{ .VariableName }}.value)
@@ -202,4 +206,5 @@ func ({{ .VariableName }} *{{ .OutputName }}) UnmarshalJSON(data []byte) error {
 	{{ .VariableName }}.value = &value
 	return nil
 }
+{{- end }}
 `
diff --git a/cmd/optional/testdata/optional_bar.go b/cmd/optional/testdata/optional_bar.go
index 01c9307..c796b37 100644
--- a/cmd/optional/testdata/optional_bar.go
+++ b/cmd/optional/testdata/optional_bar.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 17:57:17.641444 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:22:57.093409 +0000 UTC
 
 package bar
 
diff --git a/cmd/optional/testdata/optional_foo.go b/cmd/optional/testdata/optional_foo.go
index 18a2c24..a60f7e9 100644
--- a/cmd/optional/testdata/optional_foo.go
+++ b/cmd/optional/testdata/optional_foo.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 17:57:17.640425 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:22:57.092747 +0000 UTC
 
 package foo
 
diff --git a/cmd/optional/testdata/string.go b/cmd/optional/testdata/string.go
index 64074b9..8ed6bb5 100644
--- a/cmd/optional/testdata/string.go
+++ b/cmd/optional/testdata/string.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 17:57:17.639386 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:22:57.091816 +0000 UTC
 
 package optional
 
diff --git a/complex128.go b/complex128.go
index b85dfbe..2200dc9 100644
--- a/complex128.go
+++ b/complex128.go
@@ -1,10 +1,9 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:54.128811 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:38.633502 +0000 UTC
 
 package optional
 
 import (
-	"encoding/json"
 	"errors"
 )
 
@@ -51,27 +50,3 @@ func (c Complex128) If(fn func(complex128)) {
 		fn(*c.value)
 	}
 }
-
-func (c Complex128) MarshalJSON() ([]byte, error) {
-	if c.Present() {
-		return json.Marshal(c.value)
-	}
-	return json.Marshal(nil)
-}
-
-func (c *Complex128) UnmarshalJSON(data []byte) error {
-
-	if string(data) == "null" {
-		c.value = nil
-		return nil
-	}
-
-	var value complex128
-
-	if err := json.Unmarshal(data, &value); err != nil {
-		return err
-	}
-
-	c.value = &value
-	return nil
-}
diff --git a/complex64.go b/complex64.go
index 04d5ee5..9d07d4a 100644
--- a/complex64.go
+++ b/complex64.go
@@ -1,10 +1,9 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:54.464548 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:39.017904 +0000 UTC
 
 package optional
 
 import (
-	"encoding/json"
 	"errors"
 )
 
@@ -51,27 +50,3 @@ func (c Complex64) If(fn func(complex64)) {
 		fn(*c.value)
 	}
 }
-
-func (c Complex64) MarshalJSON() ([]byte, error) {
-	if c.Present() {
-		return json.Marshal(c.value)
-	}
-	return json.Marshal(nil)
-}
-
-func (c *Complex64) UnmarshalJSON(data []byte) error {
-
-	if string(data) == "null" {
-		c.value = nil
-		return nil
-	}
-
-	var value complex64
-
-	if err := json.Unmarshal(data, &value); err != nil {
-		return err
-	}
-
-	c.value = &value
-	return nil
-}
diff --git a/error.go b/error.go
index bc79ddc..ff6c62e 100644
--- a/error.go
+++ b/error.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:54.804224 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:39.403027 +0000 UTC
 
 package optional
 
diff --git a/float32.go b/float32.go
index 9f42c2c..bdff83b 100644
--- a/float32.go
+++ b/float32.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:55.1819 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:39.935633 +0000 UTC
 
 package optional
 
diff --git a/float64.go b/float64.go
index 15966b6..640cbe8 100644
--- a/float64.go
+++ b/float64.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:55.521255 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:41.277145 +0000 UTC
 
 package optional
 
diff --git a/int.go b/int.go
index caead99..bf9fcae 100644
--- a/int.go
+++ b/int.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:55.863991 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:41.676284 +0000 UTC
 
 package optional
 
diff --git a/int16.go b/int16.go
index 9532996..37ab9c0 100644
--- a/int16.go
+++ b/int16.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:56.212093 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:42.065863 +0000 UTC
 
 package optional
 
diff --git a/int32.go b/int32.go
index 07c212d..8dd9690 100644
--- a/int32.go
+++ b/int32.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:56.641482 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:42.453259 +0000 UTC
 
 package optional
 
diff --git a/int64.go b/int64.go
index 7f8f01c..dbfd972 100644
--- a/int64.go
+++ b/int64.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:57.002648 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:42.850127 +0000 UTC
 
 package optional
 
diff --git a/int8.go b/int8.go
index 182f814..f63b049 100644
--- a/int8.go
+++ b/int8.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:57.555216 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:43.246461 +0000 UTC
 
 package optional
 
diff --git a/rune.go b/rune.go
index 469de67..bc5e8cc 100644
--- a/rune.go
+++ b/rune.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:57.969673 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:43.637876 +0000 UTC
 
 package optional
 
diff --git a/string.go b/string.go
index 19e67c1..4c04341 100644
--- a/string.go
+++ b/string.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:58.516631 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:44.022296 +0000 UTC
 
 package optional
 
diff --git a/uint.go b/uint.go
index 33e93e3..2093dfa 100644
--- a/uint.go
+++ b/uint.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:58.898667 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:44.406039 +0000 UTC
 
 package optional
 
diff --git a/uint16.go b/uint16.go
index 428ecbf..fd0726e 100644
--- a/uint16.go
+++ b/uint16.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:59.455534 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:44.798325 +0000 UTC
 
 package optional
 
diff --git a/uint32.go b/uint32.go
index 5fa2ebf..8f43dd3 100644
--- a/uint32.go
+++ b/uint32.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:29:59.856381 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:45.183474 +0000 UTC
 
 package optional
 
diff --git a/uint64.go b/uint64.go
index f0d79a4..a25012d 100644
--- a/uint64.go
+++ b/uint64.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:30:00.317311 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:45.675831 +0000 UTC
 
 package optional
 
diff --git a/uint8.go b/uint8.go
index 9b2be7f..ed1cd24 100644
--- a/uint8.go
+++ b/uint8.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:30:00.699077 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:46.066068 +0000 UTC
 
 package optional
 
diff --git a/uintptr.go b/uintptr.go
index af79fef..1828213 100644
--- a/uintptr.go
+++ b/uintptr.go
@@ -1,5 +1,5 @@
 // Code generated by go generate
-// This file was generated by robots at 2018-12-06 14:30:01.109101 +0000 UTC
+// This file was generated by robots at 2021-05-03 20:24:46.705499 +0000 UTC
 
 package optional