diff --git a/packages/kit/src/core/config/options.js b/packages/kit/src/core/config/options.js
index 7445558bbda4..32d8ca1cdf01 100644
--- a/packages/kit/src/core/config/options.js
+++ b/packages/kit/src/core/config/options.js
@@ -257,15 +257,13 @@ const options = object(
 
 				// TODO: remove this for the 1.0 release
 				force: validate(undefined, (input, keypath) => {
-					if (typeof input !== 'undefined') {
-						const new_input = input ? 'warn' : 'fail';
-						const needs_option = new_input === 'warn';
-						throw new Error(
-							`${keypath} has been removed in favor of \`handleHttpError\`. In your case, set \`handleHttpError\` to "${new_input}"${
-								needs_option ? '' : ' (or leave it undefined)'
-							} to get the same behavior as you would with \`force: ${JSON.stringify(input)}\``
-						);
-					}
+					const new_input = input ? 'warn' : 'fail';
+					const needs_option = new_input === 'warn';
+					throw new Error(
+						`${keypath} has been removed in favor of \`handleHttpError\`. In your case, set \`handleHttpError\` to "${new_input}"${
+							needs_option ? '' : ' (or leave it undefined)'
+						} to get the same behavior as you would with \`force: ${JSON.stringify(input)}\``
+					);
 				}),
 
 				handleHttpError: validate('fail', (input, keypath) => {
@@ -282,15 +280,13 @@ const options = object(
 
 				// TODO: remove this for the 1.0 release
 				onError: validate(undefined, (input, keypath) => {
-					if (typeof input !== 'undefined') {
-						let message = `${keypath} has been renamed to \`handleHttpError\``;
-
-						if (input === 'continue') {
-							message += ', and "continue" has been renamed to "warn"';
-						}
+					let message = `${keypath} has been renamed to \`handleHttpError\``;
 
-						throw new Error(message);
+					if (input === 'continue') {
+						message += ', and "continue" has been renamed to "warn"';
 					}
+
+					throw new Error(message);
 				}),
 
 				origin: validate('http://sveltekit-prerender', (input, keypath) => {
@@ -432,8 +428,6 @@ function string(fallback, allow_empty = true) {
  */
 function string_array(fallback) {
 	return validate(fallback, (input, keypath) => {
-		if (input === undefined) return input;
-
 		if (!Array.isArray(input) || input.some((value) => typeof value !== 'string')) {
 			throw new Error(`${keypath} must be an array of strings, if specified`);
 		}
@@ -511,10 +505,8 @@ function assert_string(input, keypath) {
 
 /** @param {(keypath?: string) => string} fn */
 function error(fn) {
-	return validate(undefined, (input, keypath) => {
-		if (input !== undefined) {
-			throw new Error(fn(keypath));
-		}
+	return validate(undefined, (_, keypath) => {
+		throw new Error(fn(keypath));
 	});
 }