Fix assigning a partial pagination object to Options

Setting `options.pagination = {paginate}` outside of `merge()` replaced the whole pagination object, which dropped the defaults that the pagination logic asserts on. The setter now keeps the existing settings, like the `retry` setter.

Author: sindresorhus

source/core/options.ts

@@ -3307,7 +3307,8 @@ export default class Options {
 		if (this.#merging) {
 			safeObjectAssign(this.#internals.pagination, value);
 		} else {
-			this.#internals.pagination = value;
+			// A partial object must not drop the other pagination settings, as the pagination logic requires them.
+			this.#internals.pagination = {...this.#internals.pagination, ...value};
 		}
 	}
 

test/normalize-arguments.ts

@@ -265,3 +265,20 @@ test('assigning a partial retry object keeps the other retry defaults', t => {
 	t.is(options.retry.noise, defaults.noise);
 	t.is(options.retry.enforceRetryRules, defaults.enforceRetryRules);
 });
+
+test('assigning a partial pagination object keeps the other pagination defaults', t => {
+	const defaults = new Options().pagination;
+	const options = new Options();
+	const paginate = (): false => false;
+
+	options.pagination = {paginate};
+
+	t.is(options.pagination.paginate, paginate);
+	t.is(options.pagination.transform, defaults.transform);
+	t.is(options.pagination.filter, defaults.filter);
+	t.is(options.pagination.shouldContinue, defaults.shouldContinue);
+	t.is(options.pagination.countLimit, defaults.countLimit);
+	t.is(options.pagination.requestLimit, defaults.requestLimit);
+	t.is(options.pagination.backoff, defaults.backoff);
+	t.is(options.pagination.stackAllItems, defaults.stackAllItems);
+});