fix: support documents without slugs in documentToLinkField

src/documentToLinkField.ts

@@ -4,6 +4,9 @@ import {
 	PrismicDocument,
 } from "@prismicio/types";
 
+type SetOptional<T, Keys extends keyof T> = Omit<T, Keys> &
+	Partial<Pick<T, Keys>>;
+
 /**
  * Converts a document into a link field, this is useful when crawling the API
  * for document links
@@ -14,7 +17,9 @@ import {
  * @returns The equivalent link field to use with `asLink()`
  * @internal
  */
-export const documentToLinkField = <TDocument extends PrismicDocument>(
+export const documentToLinkField = <
+	TDocument extends SetOptional<PrismicDocument, "slugs">,
+>(
 	prismicDocument: TDocument,
 ): FilledLinkToDocumentField<
 	TDocument["type"],

test/documentToLinkField.test.ts

@@ -65,3 +65,25 @@ test("returns equivalent link field from given document with non-empty data", (t
 		data: { foo: "bar" },
 	});
 });
+
+// This test checks support for Gatsby users. The `slugs` field is not
+// queriable in Gatsby since it is deprecated.
+// Deprecation info: https://community.prismic.io/t/what-are-slugs/6493
+test("supports documents without slugs field", (t) => {
+	const document = {
+		...documentFixture.empty,
+		url: null,
+		slugs: undefined,
+	};
+
+	t.deepEqual(documentToLinkField(document), {
+		link_type: LinkType.Document,
+		id: "XvoFFREAAM0WGBng",
+		uid: "test",
+		type: "page",
+		tags: [],
+		lang: "en-us",
+		url: undefined,
+		slug: undefined,
+	});
+});