feat: add toYaml and fromYaml to functions map

pkg/document/template.go

@@ -10,7 +10,6 @@ import (
 
 	"github.com/norwoodj/helm-docs/pkg/util"
 
-	"github.com/Masterminds/sprig/v3"
 	log "github.com/sirupsen/logrus"
 
 	"github.com/norwoodj/helm-docs/pkg/helm"
@@ -359,7 +358,7 @@ func getDocumentationTemplates(chartDirectory string, chartSearchRoot string, te
 
 func newChartDocumentationTemplate(chartDocumentationInfo helm.ChartDocumentationInfo, chartSearchRoot string, templateFiles []string, badgeStyle string) (*template.Template, error) {
 	documentationTemplate := template.New(chartDocumentationInfo.ChartDirectory)
-	documentationTemplate.Funcs(sprig.TxtFuncMap())
+	documentationTemplate.Funcs(util.FuncMap())
 	goTemplateList, err := getDocumentationTemplates(chartDocumentationInfo.ChartDirectory, chartSearchRoot, templateFiles, badgeStyle)
 
 	if err != nil {

pkg/util/funcs.go

@@ -0,0 +1,44 @@
+package util
+
+import (
+	"strings"
+	"text/template"
+
+	"github.com/Masterminds/sprig/v3"
+	"gopkg.in/yaml.v3"
+)
+
+func FuncMap() template.FuncMap {
+	f := sprig.TxtFuncMap()
+	f["toYaml"] = toYAML
+	f["fromYaml"] = fromYAML
+	return f
+}
+
+// toYAML takes an interface, marshals it to yaml, and returns a string. It will
+// always return a string, even on marshal error (empty string).
+//
+// This is designed to be called from a template.
+func toYAML(v interface{}) string {
+	data, err := yaml.Marshal(v)
+	if err != nil {
+		// Swallow errors inside of a template.
+		return ""
+	}
+	return strings.TrimSuffix(string(data), "\n")
+}
+
+// fromYAML converts a YAML document into a map[string]interface{}.
+//
+// This is not a general-purpose YAML parser, and will not parse all valid
+// YAML documents. Additionally, because its intended use is within templates
+// it tolerates errors. It will insert the returned error message string into
+// m["Error"] in the returned map.
+func fromYAML(str string) map[string]interface{} {
+	m := map[string]interface{}{}
+
+	if err := yaml.Unmarshal([]byte(str), &m); err != nil {
+		m["Error"] = err.Error()
+	}
+	return m
+}