Having child on extras provides better developer experience

pino.d.ts

@@ -730,18 +730,6 @@ declare namespace P {
     type Logger = BaseLogger & LoggerExtras & Record<string, any>;
 
     interface BaseLogger {
-        /**
-         * Creates a child logger, setting all key-value pairs in `bindings` as properties in the log lines. All serializers will be applied to the given pair.
-         * Child loggers use the same output stream as the parent and inherit the current log level of the parent at the time they are spawned.
-         * From v2.x.x the log level of a child is mutable (whereas in v1.x.x it was immutable), and can be set independently of the parent.
-         * If a `level` property is present in the object passed to `child` it will override the child logger level.
-         *
-         * @param bindings: an object of key-value pairs to include in log lines as properties.
-         * @param options: an options object that will override child logger inherited options.
-         * @returns a child logger instance.
-         */
-        child(bindings: Bindings, options?: ChildLoggerOptions): BaseLogger;
-
         /**
          * Set this property to the desired logging level. In order of priority, available levels are:
          *
@@ -850,6 +838,18 @@ declare namespace P {
          */
         levelVal: number;
 
+        /**
+         * Creates a child logger, setting all key-value pairs in `bindings` as properties in the log lines. All serializers will be applied to the given pair.
+         * Child loggers use the same output stream as the parent and inherit the current log level of the parent at the time they are spawned.
+         * From v2.x.x the log level of a child is mutable (whereas in v1.x.x it was immutable), and can be set independently of the parent.
+         * If a `level` property is present in the object passed to `child` it will override the child logger level.
+         *
+         * @param bindings: an object of key-value pairs to include in log lines as properties.
+         * @param options: an options object that will override child logger inherited options.
+         * @returns a child logger instance.
+         */
+        child(bindings: Bindings, options?: ChildLoggerOptions): Logger;
+
         /**
          * Registers a listener function that is triggered when the level is changed.
          * Note: When browserified, this functionality will only be available if the `events` module has been required elsewhere

test/types/pino.test-d.ts

@@ -93,7 +93,7 @@ child.level = "info";
 child.info("hooray");
 log.info("nope nope nope");
 log.child({ foo: "bar" }, { level: "debug" }).debug("debug!");
-(child as Logger).bindings();
+child.bindings();
 const customSerializers = {
     test() {
         return "this is my serializer";