gohugoio/hugo · error

{key} is neither a field nor a method of Page

Error message

{key} is neither a field nor a method of Page

What it means

`GroupBy` first looks the key up as a method; if not found it tries the Page struct field via `FieldByName` (pagegroup.go:141-143). If neither matches, the key is genuinely unknown and grouping cannot proceed.

Source

Thrown at resources/page/pagegroup.go:143

	var ft any
	index := hreflect.GetMethodIndexByName(pagePtrType, key)
	if index != -1 {
		m := pagePtrType.Method(index)
		if m.Type.NumOut() == 0 || m.Type.NumOut() > 2 {
			return nil, errors.New(key + " is a Page method but you can't use it with GroupBy")
		}
		if m.Type.NumOut() == 1 && m.Type.Out(0).Implements(errorType) {
			return nil, errors.New(key + " is a Page method but you can't use it with GroupBy")
		}
		if m.Type.NumOut() == 2 && !m.Type.Out(1).Implements(errorType) {
			return nil, errors.New(key + " is a Page method but you can't use it with GroupBy")
		}
		ft = m
	} else {
		var ok bool
		ft, ok = pagePtrType.Elem().FieldByName(key)
		if !ok {
			return nil, errors.New(key + " is neither a field nor a method of Page")
		}
	}

	var tmp reflect.Value
	switch e := ft.(type) {
	case reflect.StructField:
		tmp = reflect.MakeMap(reflect.MapOf(e.Type, pagesType))
	case reflect.Method:
		tmp = reflect.MakeMap(reflect.MapOf(e.Type.Out(0), pagesType))
	}

	for _, e := range p {
		ppv := reflect.ValueOf(e)
		var fv reflect.Value
		switch ft.(type) {
		case reflect.StructField:
			fv = ppv.Elem().FieldByName(key)
		case reflect.Method:

View on GitHub (pinned to 52c9bd7908)

Solutions

1. Verify the name is an exported Page field or method (see Hugo's Page object docs).
2. For front-matter params, use `{{ .Pages.GroupByParam "myparam" }}` instead of GroupBy.
3. Check spelling and capitalization.

Example fix

{{/* before: not a Page field/method */}}
{{ .Pages.GroupBy "myauthor" }}

{{/* after: group by a front matter param */}}
{{ .Pages.GroupByParam "myauthor" }}

When it happens

Trigger: Calling `{{ .Pages.GroupBy "Foo" }}` where `Foo` is neither an exported Page method nor an exported Page struct field — e.g. a typo, a param name, or a removed field.

Common situations: Typo in the field/method name; trying to group by a front-matter param (use GroupByParam instead); referencing a field removed in a Hugo version upgrade; case sensitivity mistakes.

Related errors

• {key} is a Page method but you can't use it with GroupBy
• can't apply the operator to the values
• quality ranges from 1 to 100 inclusive
• invalid image dimensions
• must provide Width and Height

AI-assisted analysis of gohugoio/hugo@52c9bd7908 (2026-08-09). Data as JSON: /api/errors/e65faacdbf09fe79. Report an issue: GitHub.