feat: add plugin for time

docs/static/llms.txt

@@ -202,6 +202,7 @@ observable.Subscribe(ro.OnNext(func(s string) {
 - **bytes** - Byte slice manipulation operators
 - **strings** - String manipulation operators (Capitalize, CamelCase, SnakeCase, etc.)
 - **sort** - Sorting operators
+- **time** - Time manipulation
 
 ### Encoding & Serialization
 - **encoding/json** - JSON marshaling and unmarshaling

go.mod

@@ -17,4 +17,4 @@ require (
 	golang.org/x/text v0.22.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-)
+)

go.work

@@ -52,6 +52,7 @@ use (
 	./plugins/strings
 	./plugins/template
 	./plugins/testify
+	./plugins/time
 	./plugins/websocket/client
 )
 

plugins/time/README.md

@@ -0,0 +1,170 @@
+# Time Plugin
+
+The time plugin provides operators for manipulating dates/time object in reactive streams.
+
+## Installation
+
+```bash
+go get github.com/samber/ro/plugins/time
+```
+
+## Operators
+
+### Add
+
+Add a duration to a date
+
+```go
+import (
+    "github.com/samber/ro"
+    rotime "github.com/samber/ro/plugins/time"
+)
+
+observable := ro.Pipe1(
+    ro.Just(
+        time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC),
+        time.Date(0, time.January, 1, 23, 59, 59, 0, time.UTC),
+    ),
+    rotime.Add(2 * time.Hour),
+)
+
+// Output:
+// Next: time.Date(2026, time.January, 7, 16, 30, 0, 0, time.UTC)
+// Next: time.Date(0, time.January, 2, 1, 59, 59, 0, time.UTC)
+// Completed
+```
+
+### AddDate
+
+Add a duration defined by years, months, days to a date.
+
+```go
+import (
+    "github.com/samber/ro"
+    rotime "github.com/samber/ro/plugins/time"
+)
+
+observable := ro.Pipe1(
+    ro.Just(
+        time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC),
+    ),
+    rotime.AddDate(0, 1, 0),
+)
+
+// Output:
+// Next: time.Date(2026, time.February, 7, 14, 30, 0, 0, time.UTC)
+// Completed
+```
+
+### Format
+
+Transform an observable time.Time into a string, formatted according to the provided layout.
+
+```go
+import (
+    "github.com/samber/ro"
+    rotime "github.com/samber/ro/plugins/time"
+)
+
+observable := ro.Pipe1(
+    ro.Just(
+        time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC),
+    ),
+    rotime.Format("2006-01-02 15:04:05"),
+)
+
+// Output:
+// Next: "2026-01-07 14:30:00"
+// Completed
+```
+
+### In
+
+Transform an observable time.Time into a string, formatted according to the provided layout.
+
+```go
+import (
+    "github.com/samber/ro"
+    rotime "github.com/samber/ro/plugins/time"
+)
+
+observable := ro.Pipe1(
+    ro.Just(
+       time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC),
+    ),
+    rotime.In(time.LoadLocation("Europe/Paris")),
+)
+
+// Output:
+// Next: time.Date(2026, time.January, 7, 16, 30, 0, 0, time.CET),
+// Completed
+```
+
+### Parse
+
+Transform an observable string into an observable of time.Time.
+
+```go
+import (
+    "github.com/samber/ro"
+    rotime "github.com/samber/ro/plugins/time"
+)
+
+observable := ro.Pipe1(
+    ro.Just(
+      "2026-01-07 14:30:00",
+    ),
+    rotime.Parse("2006-01-02 15:04:05"),
+)
+
+// Output:
+// Next: time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC)
+// Completed
+```
+
+### ParseInLocation
+
+Transform an observable string into an observable of time.Time, using location.
+
+```go
+import (
+    "github.com/samber/ro"
+    rotime "github.com/samber/ro/plugins/time"
+)
+
+observable := ro.Pipe1(
+    ro.Just(
+      "2026-01-07 14:30:00",
+    ),
+    rotime.ParseInLocation("2006-01-02 15:04:05", time.UTC),
+)
+
+// Output:
+// Next: time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC)
+// Completed
+```
+
+### StartOfDay
+
+Truncates the time to the beginning of its day in the local time zone
+
+```go
+import (
+    "github.com/samber/ro"
+    rotime "github.com/samber/ro/plugins/time"
+)
+
+observable := ro.Pipe1(
+    ro.Just(
+      time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC),
+    ),
+    rotime.StartOfDay(),
+)
+
+// Output:
+// Next: time.Date(2026, time.January, 7, 0, 0, 0, 0, time.UTC)
+// Completed
+```
+
+## Performance Considerations
+- The time plugin uses Go's standard `time` package for operations

plugins/time/go.mod

@@ -0,0 +1,17 @@
+module github.com/samber/ro/plugins/time
+
+go 1.18
+
+require (
+	github.com/samber/ro v0.2.0
+	github.com/stretchr/testify v1.11.1
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/samber/lo v1.52.0 // indirect
+	golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17 // indirect
+	golang.org/x/text v0.22.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

plugins/time/go.sum

@@ -0,0 +1,20 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/samber/lo v1.52.0 h1:Rvi+3BFHES3A8meP33VPAxiBZX/Aws5RxrschYGjomw=
+github.com/samber/lo v1.52.0/go.mod h1:4+MXEGsJzbKGaUEQFKBq2xtfuznW9oz/WrgyzMzRoM0=
+github.com/samber/ro v0.2.0 h1:pwhLFGZprz+3KyE3JIUnv8GGF/ADpIpvFUEDxuzfGbY=
+github.com/samber/ro v0.2.0/go.mod h1:eInj5R1BbXfGoT1ef0HIO5Qie0wlPkkyL0koOaEmfNM=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17 h1:3MTrJm4PyNL9NBqvYDSj3DHl46qQakyfqfWo4jgfaEM=
+golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17/go.mod h1:lgLbSvA5ygNOMpwM/9anMpWVlVJ7Z+cHWq/eFuinpGE=
+golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
+golang.org/x/text v0.22.0/go.mod h1:YRoo4H8PVmsu+E3Ou7cqLVH8oXWIHVoX0jqUWALQhfY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

plugins/time/operator_add.go

@@ -0,0 +1,57 @@
+// Copyright 2025 samber.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://github.com/samber/ro/blob/main/licenses/LICENSE.apache.md
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rotime
+
+import (
+	"time"
+
+	"github.com/samber/ro"
+)
+
+// Add returns an operator that adds a fixed duration to each time value.
+//
+// Example:
+//
+//	obs := ro.Pipe1(
+//	    ro.Just(time.Now()),
+//	    rotime.Add(2*time.Hour),
+//	)
+//
+// The observable then emits: time.Now().Add(2 * time.Hour).
+func Add(d time.Duration) func(destination ro.Observable[time.Time]) ro.Observable[time.Time] {
+	return ro.Map(
+		func(value time.Time) time.Time {
+			return value.Add(d)
+		},
+	)
+}
+
+// AddDate returns an operator that adds a date offset (years, months, days) to each time value.
+//
+// Example:
+//
+//	obs := ro.Pipe1(
+//	    ro.Just(time.Date(2026, time.January, 7, 14, 30, 0, 0, time.UTC)),
+//	    rotime.AddDate(0, 1, 0),
+//	)
+//
+// The observable then emits: time.Date(2026, time.February, 7, 14, 30, 0, 0, time.UTC).
+func AddDate(years int, months int, days int) func(destination ro.Observable[time.Time]) ro.Observable[time.Time] {
+	return ro.Map(
+		func(value time.Time) time.Time {
+			return value.AddDate(years, months, days)
+		},
+	)
+}