Add the `get-date` template helper (#262)

CHANGELOG.md

@@ -7,6 +7,14 @@ All notable changes to this project will be documented in this file.
 ### Added
 
 * LSP: Support for external URLs with `documentLink`.
+* New `{{get-date}}` template helper to obtain a date object from natural language.
+    ```
+    Get a relative date using natural language:
+    {{get-date "next week"}}
+
+    Format a date returned by `get-date`:
+    {{date (get-date "monday") "timestamp"}}
+    ```
 
 ### Fixed
 

internal/adapter/handlebars/handlebars.go

@@ -15,13 +15,14 @@ import (
 
 func Init(supportsUTF8 bool, logger util.Logger) {
 	helpers.RegisterConcat()
-	helpers.RegisterSubstring()
 	helpers.RegisterDate(logger)
+	helpers.RegisterGetDate(logger)
 	helpers.RegisterJoin()
 	helpers.RegisterJSON(logger)
 	helpers.RegisterList(supportsUTF8)
 	helpers.RegisterPrepend(logger)
 	helpers.RegisterShell(logger)
+	helpers.RegisterSubstring()
 }
 
 // Template renders a parsed handlebars template.

internal/adapter/handlebars/handlebars_test.go

@@ -241,6 +241,11 @@ func TestDateHelper(t *testing.T) {
 	testString(t, "{{date now 'elapsed'}}", context, "13 years ago")
 }
 
+func TestGetDateHelper(t *testing.T) {
+	context := map[string]interface{}{"now": time.Date(2009, 11, 17, 20, 34, 58, 651387237, time.UTC)}
+	testString(t, "{{get-date \"2009-11-17T20:34:58\"}}", context, "2009-11-17 20:34:58 +0000 UTC")
+}
+
 func TestShellHelper(t *testing.T) {
 	// block is passed as piped input
 	testString(t,

internal/adapter/handlebars/helpers/getdate.go

@@ -0,0 +1,23 @@
+package helpers
+
+import (
+	"time"
+
+	"github.com/aymerick/raymond"
+	"github.com/mickael-menu/zk/internal/util"
+	dateutil "github.com/mickael-menu/zk/internal/util/date"
+	"github.com/pkg/errors"
+)
+
+// RegisterGetDate registers the {{getdate}} template helper to use the `naturaldate` package to generate time.Time based on language strings.
+// This can be used in combination with the `date` helper to generate dates in the user's language.
+// {{date (get-date "last week") "timestamp"}}
+func RegisterGetDate(logger util.Logger) {
+	raymond.RegisterHelper("get-date", func(natural string) time.Time {
+		date, err := dateutil.TimeFromNatural(natural)
+		if err != nil {
+			logger.Err(errors.Wrap(err, "the {{get-date}} template helper failed to parse the date"))
+		}
+		return date
+	})
+}

internal/util/date/date.go

@@ -3,7 +3,7 @@ package date
 import (
 	"time"
 
-	"github.com/tj/go-naturaldate"
+	naturaldate "github.com/tj/go-naturaldate"
 )
 
 // Provider returns a date instance.