Fix date formatting

Cargo.toml

@@ -15,7 +15,8 @@ all-features = true
 
 [dependencies]
 chrono = { version = "0.4", optional = true }
-regex = { version = "1.7", optional = true }
+once_cell = { version = "1.19", optional = true }
+regex = { version = "1.10", optional = true }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 
@@ -24,4 +25,4 @@ reqwest = { version = "0.11", features = ["json"] }
 tokio = { version = "1", features = ["full"] }
 
 [features]
-fmt = ["dep:chrono", "dep:regex"]
+fmt = ["dep:chrono", "dep:once_cell", "dep:regex"]

README.md

@@ -117,15 +117,37 @@ Enable `fmt` module and format messages in [this way](https://api.slack.com/refe
 
 ```rust
 use chrono::prelude::*;
-use slack_messaging::fmt::DateFormat;
+use slack_messaging::fmt::DateFormatter;
+
+// Formatter without optional link.
+let f = DateFormatter::builder()
+ .token("{date_short} at {time}")
+ .build();
 
 let dt = DateTime::parse_from_rfc3339("2023-02-27T12:34:56+09:00").unwrap();
-let f = DateFormat::new(dt).token("{date_short} at {time}");
 
 assert_eq!(
- format!("{f}"),
+ f.format(&dt),
  "<!date^1677468896^{date_short} at {time}|Feb 27, 2023 at 12:34 PM>"
 );
+
+// You can also set optional link when formatting.
+assert_eq!(
+ f.format_with_link(&dt, "https://example.com"),
+ "<!date^1677468896^{date_short} at {time}^https://example.com|Feb 27, 2023 at 12:34 PM>"
+);
+
+// Formatter with optional link.
+let f = DateFormatter::builder()
+ .token("{date_short} at {time}")
+ .link("https://example.com")
+ .build();
+
+// This time, format method returns text with link set to the formatter.
+assert_eq!(
+ f.format(&dt),
+ "<!date^1677468896^{date_short} at {time}^https://example.com|Feb 27, 2023 at 12:34 PM>"
+);
 ```
 
 ## License