add creation-date-key modification-date-key` configuration options

These two configuration options are used to change the way zk obtains
the creation date and modification date from a file.

Author: y86-dev

docs/notes/note-format.md

@@ -23,6 +23,18 @@ You can set up some features of `zk`'s Markdown parser from your
 
 [1]: https://blog.bear.app/2017/11/bear-tips-how-to-create-multi-word-tags/
 
+### `YAML` Frontmatter
+
+The following configuration options are available for changing `zk`'s interactions with the
+frontmatter:
+
+| Setting                 | Default   | Description                                                     |
+| ----------------------- | --------- | --------------------------------------------------------------- |
+| `creation-date-key`     | `"date"`  | Yaml key used to store the creation date & time of the file     |
+| `modification-date-key` | none [^2] | Yaml key used to store the modification date & time of the file |
+
+[^2]: When this value is not set, the file's modification date is taken from the filesystem.
+
 ### Customizing the Markdown links generated by `zk`
 
 By default, `zk` will generate regular Markdown links for internal links. If you

docs/notes/note-frontmatter.md

@@ -26,3 +26,6 @@ keywords: [writing, essay, practice]
 All metadata are indexed and can be printed in `zk list` output, using the
 template variable `{{metadata.<key>}}`, e.g. `{{metadata.description}}`. The
 keys are normalized to lower case.
+
+Some of the keys above can be changed by the configuration file, see [`YAML`
+Frontmatter](note-format.md#yaml-frontmatter).

internal/core/config.go

@@ -57,6 +57,10 @@ func NewDefaultConfig() Config {
 				LinkFormat:        "markdown",
 				LinkEncodePath:    true,
 				LinkDropExtension: true,
+                Frontmatter:       YamlFrontmatterConfig{
+                    CreationDate:     "date",
+                    ModificationDate: opt.NullString,
+                },
 			},
 		},
 		LSP: LSPConfig{
@@ -161,6 +165,18 @@ type MarkdownConfig struct {
 	LinkEncodePath bool
 	// Indicates whether a link's path file extension will be removed.
 	LinkDropExtension bool
+
+	// Frontmatter determines the keys used in the frontmatter
+	Frontmatter YamlFrontmatterConfig
+}
+
+// YamlFrontmatterConfig holds the configuration for Yaml frontmatter.
+type YamlFrontmatterConfig struct {
+	// CreationDate indicates what name the key for the creation date has. Default is "date"
+	CreationDate     string
+	// ModificationDate indicates what name the key for the modification date has. If not present,
+	// the filesystems modification time is used.
+	ModificationDate opt.String
 }
 
 // ToolConfig holds the external tooling configuration.
@@ -391,6 +407,21 @@ func ParseConfig(content []byte, path string, parentConfig Config, isGlobal bool
 		config.Format.Markdown.LinkDropExtension = *markdown.LinkDropExtension
 	}
 
+    // Frontmatter
+    frontmatter := markdown.Frontmatter
+    if frontmatter.CreationDate != nil && *frontmatter.CreationDate == "" {
+        *frontmatter.CreationDate = "date"
+    }
+    if frontmatter.CreationDate != nil {
+        config.Format.Markdown.Frontmatter.CreationDate = *frontmatter.CreationDate
+    }
+    if frontmatter.ModificationDate != nil && *frontmatter.ModificationDate == "" {
+        frontmatter.ModificationDate = nil
+    }
+    if frontmatter.ModificationDate != nil {
+        config.Format.Markdown.Frontmatter.ModificationDate = opt.NewString(*frontmatter.ModificationDate)
+    }
+
 	// Tool
 	tool := tomlConf.Tool
 	if tool.Editor != nil {
@@ -554,12 +585,18 @@ type tomlFormatConfig struct {
 }
 
 type tomlMarkdownConfig struct {
-	Hashtags          *bool   `toml:"hashtags"`
-	ColonTags         *bool   `toml:"colon-tags"`
-	MultiwordTags     *bool   `toml:"multiword-tags"`
-	LinkFormat        *string `toml:"link-format"`
-	LinkEncodePath    *bool   `toml:"link-encode-path"`
-	LinkDropExtension *bool   `toml:"link-drop-extension"`
+	Hashtags          *bool                     `toml:"hashtags"`
+	ColonTags         *bool                     `toml:"colon-tags"`
+	MultiwordTags     *bool                     `toml:"multiword-tags"`
+	LinkFormat        *string                   `toml:"link-format"`
+	LinkEncodePath    *bool                     `toml:"link-encode-path"`
+	LinkDropExtension *bool                     `toml:"link-drop-extension"`
+	Frontmatter       tomlYamlFrontmatterConfig `toml:"frontmatter"`
+}
+
+type tomlYamlFrontmatterConfig struct {
+	CreationDate     *string `toml:"creation-date-key"`
+	ModificationDate *string `toml:"modification-date-key"`
 }
 
 type tomlToolConfig struct {

internal/core/config_test.go

@@ -39,6 +39,10 @@ func TestParseDefaultConfig(t *testing.T) {
 				LinkFormat:        "markdown",
 				LinkEncodePath:    true,
 				LinkDropExtension: true,
+                Frontmatter:       YamlFrontmatterConfig{
+                    CreationDate:     "date",
+                    ModificationDate: opt.NullString,
+                },
 			},
 		},
 		Tool: ToolConfig{
@@ -91,6 +95,10 @@ func TestParseComplete(t *testing.T) {
 		link-encode-path = true
 		link-drop-extension = false
 
+        [format.markdown.frontmatter]
+        creation-date-key = "created"
+        modification-date-key = "changed"
+
 		[tool]
 		editor = "vim"
 		shell = "/bin/bash"
@@ -235,6 +243,10 @@ func TestParseComplete(t *testing.T) {
 				LinkFormat:        "custom",
 				LinkEncodePath:    true,
 				LinkDropExtension: false,
+                Frontmatter:       YamlFrontmatterConfig {
+                    CreationDate:     "created",
+                    ModificationDate: opt.NewString("changed"),
+                },
 			},
 		},
 		Tool: ToolConfig{
@@ -421,6 +433,10 @@ func TestParseMergesGroupConfig(t *testing.T) {
 				LinkFormat:        "markdown",
 				LinkEncodePath:    true,
 				LinkDropExtension: true,
+                Frontmatter:       YamlFrontmatterConfig{
+                    CreationDate:     "date",
+                    ModificationDate: opt.NullString,
+                },
 			},
 		},
 		LSP: LSPConfig{

internal/core/note_parse.go

@@ -94,16 +94,16 @@ func (n *Notebook) ParseNoteWithContent(absPath string, content []byte) (*Note,
 
 	times, err := times.Stat(absPath)
 	if err == nil {
-		note.Modified = times.ModTime().UTC()
-		note.Created = creationDateFrom(note.Metadata, times)
+		note.Modified = n.modificationDateFrom(note.Metadata, times)
+		note.Created = n.creationDateFrom(note.Metadata, times)
 	}
 
 	return &note, nil
 }
 
-func creationDateFrom(metadata map[string]interface{}, times times.Timespec) time.Time {
+func (n *Notebook) creationDateFrom(metadata map[string]interface{}, times times.Timespec) time.Time {
 	// Read the creation date from the YAML frontmatter `date` key.
-	if dateVal, ok := metadata["date"]; ok {
+	if dateVal, ok := metadata[n.Config.Format.Markdown.Frontmatter.CreationDate]; ok {
 		if dateStr, ok := dateVal.(string); ok {
 			if time, err := iso8601.ParseString(dateStr); err == nil {
 				return time
@@ -124,3 +124,24 @@ func creationDateFrom(metadata map[string]interface{}, times times.Timespec) tim
 
 	return time.Now().UTC()
 }
+
+func (n *Notebook) modificationDateFrom(metadata map[string]interface{}, times times.Timespec) time.Time {
+	configKey := n.Config.Format.Markdown.Frontmatter.ModificationDate
+	if !configKey.IsNull() {
+		if dateVal, ok := metadata[configKey.Unwrap()]; ok {
+			if dateStr, ok := dateVal.(string); ok {
+				if time, err := iso8601.ParseString(dateStr); err == nil {
+					return time
+				}
+				// Omitting the `T` is common
+				if time, err := time.Parse("2006-01-02 15:04:05", dateStr); err == nil {
+					return time
+				}
+				if time, err := time.Parse("2006-01-02 15:04", dateStr); err == nil {
+					return time
+				}
+			}
+		}
+	}
+	return times.ModTime().UTC()
+}

tests/config-format-markdown-frontmatter-creation-date.tesh

@@ -0,0 +1,7 @@
+$ cd blank
+
+$ echo "[format.markdown.frontmatter] creation-date-key = \"created\"" > .zk/config.toml
+
+$ echo "---\ncreated: 2025-03-27 01:18:43\n---\n\n# Note" > note.md
+$ zk list -qflink
+>{"filename":"note"}

tests/config-format-markdown-frontmatter-modification-date.tesh

@@ -0,0 +1,7 @@
+$ cd blank
+
+$ echo "[format.markdown.frontmatter] modification-date-key = \"changed\"" > .zk/config.toml
+
+$ echo "---\nchanged: 2025-03-27 01:18:43\n---\n\n# Note" > note.md
+$ zk list -qflink
+>{"filename":"note"}