feat: allow to specify serializer function children type for composeS…

…erializer function

src/composeSerializers.ts

@@ -22,22 +22,29 @@ export const composeSerializers = <SerializerReturnType>(
 	...serializers: [
 		(
 			| RichTextFunctionSerializer<SerializerReturnType>
-			| RichTextFunctionSerializer<SerializerReturnType | null>
+			| RichTextFunctionSerializer<
+					SerializerReturnType | null,
+					SerializerReturnType
+			  >
 		),
 		...(
 			| RichTextFunctionSerializer<SerializerReturnType>
-			| RichTextFunctionSerializer<SerializerReturnType | null>
+			| RichTextFunctionSerializer<
+					SerializerReturnType | null,
+					SerializerReturnType
+			  >
 		)[]
 	]
 ) => {
 	return (
 		...args: Parameters<RichTextFunctionSerializer<SerializerReturnType>>
-	): SerializerReturnType => {
+	): NonNullable<SerializerReturnType> => {
 		for (let i = 0; i < serializers.length; i++) {
 			const res = serializers[i](...args);
 
-			if (res !== null) {
-				return res;
+			if (res != null) {
+				// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+				return res!;
 			}
 		}
 

src/types.ts

@@ -28,14 +28,18 @@ import {
  * Serializes a node from a rich text or title field with a function
  *
  * @typeParam ReturnType - Return type of the function serializer
+ * @typeParam ChildrenType - Type of children, defaults to provided ReturnType
  *
  * @see Templating rich text and title fields from Prismic {@link https://prismic.io/docs/technologies/templating-rich-text-and-title-fields-javascript}
  */
-export type RichTextFunctionSerializer<ReturnType> = (
+export type RichTextFunctionSerializer<
+	ReturnType,
+	ChildrenType = ReturnType,
+> = (
 	type: RichTextNodeType,
 	node: RTAnyNode,
 	text: string | undefined,
-	children: ReturnType[],
+	children: ChildrenType[],
 	key: string,
 ) => ReturnType;