📝 document console sink types

docs/api/console-sink-type.md

@@ -0,0 +1,72 @@
+---
+name: console-sink-type
+group: api
+category: sink
+update-time: 20260613
+description: Public plain console sink type used for default text console output.
+key-word:
+    - sink
+    - console
+    - type
+    - public
+---
+
+## Console-sink-type
+
+`ConsoleSink` is the public plain console sink type used for default text console output. It is the minimal built-in synchronous sink and serves as the concrete sink type returned by `console_sink()`.
+
+### Interface
+
+```moonbit
+pub struct ConsoleSink {
+  _dummy : Unit
+}
+```
+
+#### output
+
+- `ConsoleSink` - Public synchronous sink type that writes records to the console with default text formatting.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- This is a public root struct, not a type alias.
+- The current visible field is `_dummy : Unit`, which exists only to carry the concrete sink type.
+- `console_sink()` constructs this type as the simplest built-in console output path.
+- `Logger[ConsoleSink]`, `LibraryLogger[ConsoleSink]`, and default logger helpers all use this concrete sink type when no richer formatting or routing layer is introduced.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need A Typed Plain Console Sink Value
+
+When code should keep the concrete sink type visible:
+```moonbit
+let sink : ConsoleSink = console_sink()
+```
+
+In this example, the sink value stays explicit and can be passed into typed logger construction.
+
+#### When Need A Minimal Root Logger Type
+
+When logging should start from the simplest built-in console sink:
+```moonbit
+let logger : Logger[ConsoleSink] = Logger::new(console_sink(), target="app")
+```
+
+In this example, the concrete console sink type remains part of the logger type.
+
+### Error Case
+
+e.g.:
+- `ConsoleSink` itself does not have a runtime failure mode.
+
+- Console output still depends on the current runtime environment even though the sink type is always constructible.
+
+### Notes
+
+1. Use `console_sink()` when you need a value of this type.
+
+2. Use `JsonConsoleSink` or `FormattedConsoleSink` when output shape should be more explicit than the default text path.

docs/api/formatted-console-sink-type.md

@@ -0,0 +1,75 @@
+---
+name: formatted-console-sink-type
+group: api
+category: sink
+update-time: 20260613
+description: Public formatted console sink type used for RecordFormatter-driven synchronous console output.
+key-word:
+    - sink
+    - console
+    - formatter
+    - public
+---
+
+## Formatted-console-sink-type
+
+`FormattedConsoleSink` is the public console sink type used for formatter-driven text output. It is the concrete sink type returned by both `formatted_console_sink(...)` and `text_console_sink(...)`, and it stores the rendering function used for each record.
+
+### Interface
+
+```moonbit
+pub struct FormattedConsoleSink {
+  formatter : RecordFormatter
+}
+```
+
+#### output
+
+- `FormattedConsoleSink` - Public synchronous sink type that renders each record through a stored `RecordFormatter`.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- This is a public root struct, not a type alias.
+- The current field is `formatter : RecordFormatter`.
+- `formatted_console_sink(...)` constructs this type directly from a formatter function.
+- `text_console_sink(...)` also returns this same type after adapting a `TextFormatter` into a `RecordFormatter`.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need A Typed Formatter-driven Console Sink Value
+
+When code should keep the concrete formatted sink type visible:
+```moonbit
+let sink : FormattedConsoleSink = formatted_console_sink(fn(rec) { rec.message })
+```
+
+In this example, the sink value keeps the low-level formatter-driven console type explicit.
+
+#### When Need A Typed Text-formatted Console Logger
+
+When logging should preserve the formatter-backed console sink type in the logger:
+```moonbit
+let logger : Logger[FormattedConsoleSink] = Logger::new(
+  text_console_sink(text_formatter(show_timestamp=false)),
+  target="pretty",
+)
+```
+
+In this example, the concrete formatted console sink remains part of the logger type.
+
+### Error Case
+
+e.g.:
+- `FormattedConsoleSink` itself does not have a runtime failure mode.
+
+- Output readability and cost still depend on the stored formatter function and its behavior.
+
+### Notes
+
+1. Use `formatted_console_sink(...)` or `text_console_sink(...)` when you need a value of this type.
+
+2. Use `ConsoleSink` or `JsonConsoleSink` when default text or JSON output is enough and a stored formatter function is unnecessary.

docs/api/index.md

@@ -100,8 +100,11 @@ BitLogger API navigation.
 ## Sink and file
 
 - [console-sink.md](./console-sink.md)
+- [console-sink-type.md](./console-sink-type.md)
 - [json-console-sink.md](./json-console-sink.md)
+- [json-console-sink-type.md](./json-console-sink-type.md)
 - [formatted-console-sink.md](./formatted-console-sink.md)
+- [formatted-console-sink-type.md](./formatted-console-sink-type.md)
 - [text-console-sink.md](./text-console-sink.md)
 - [callback-sink.md](./callback-sink.md)
 - [formatted-callback-sink.md](./formatted-callback-sink.md)

docs/api/json-console-sink-type.md

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+---
+name: json-console-sink-type
+group: api
+category: sink
+update-time: 20260613
+description: Public JSON console sink type used for machine-readable synchronous stdout output.
+key-word:
+    - sink
+    - json
+    - type
+    - public
+---
+
+## Json-console-sink-type
+
+`JsonConsoleSink` is the public console sink type used for machine-readable JSON stdout output. It is the concrete sink type returned by `json_console_sink()` and is intended for structured log pipelines rather than human-focused text formatting.
+
+### Interface
+
+```moonbit
+pub struct JsonConsoleSink {
+  _dummy : Unit
+}
+```
+
+#### output
+
+- `JsonConsoleSink` - Public synchronous sink type that writes records to the console as JSON.
+
+### Explanation
+
+Detailed rules explaining key parameters and behaviors
+
+- This is a public root struct, not a type alias.
+- The current visible field is `_dummy : Unit`, which exists only to carry the concrete sink type.
+- `json_console_sink()` constructs this type as the built-in structured console output path.
+- `Logger[JsonConsoleSink]` keeps the concrete machine-readable console sink type visible when typed composition matters.
+
+### How to Use
+
+Here are some specific examples provided.
+
+#### When Need A Typed JSON Console Sink Value
+
+When code should keep the concrete structured console sink type visible:
+```moonbit
+let sink : JsonConsoleSink = json_console_sink()
+```
+
+In this example, the sink value stays explicit and can be passed into typed logger construction.
+
+#### When Need A Typed Structured Stdout Logger
+
+When logging should preserve the JSON console sink type in the logger:
+```moonbit
+let logger : Logger[JsonConsoleSink] = Logger::new(json_console_sink(), target="api")
+```
+
+In this example, the concrete structured stdout sink remains part of the logger type.
+
+### Error Case
+
+e.g.:
+- `JsonConsoleSink` itself does not have a runtime failure mode.
+
+- Console output still depends on the current runtime environment even though the sink type is always constructible.
+
+### Notes
+
+1. Use `json_console_sink()` when you need a value of this type.
+
+2. Use `ConsoleSink` or `FormattedConsoleSink` when output should be plain text or custom-formatted text instead of JSON.