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chore: consolidate prerender output gates into a helper #16508

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92969b8
consolidate prerender output gates into helper
Nic-Polumeyv Jul 24, 2026
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Nic-Polumeyv Jul 25, 2026
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Nic-Polumeyv Jul 25, 2026
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9 changes: 3 additions & 6 deletions packages/kit/src/runtime/server/page/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ import { compact } from '../../../utils/array.js';
import { get_status, normalize_error } from '../../../utils/error.js';
import { noop } from '../../../utils/functions.js';
import { add_data_suffix } from '../../pathname.js';
import { redirect_response } from '../utils.js';
import { redirect_response, renders_prerendered_output } from '../utils.js';
import { static_error_page, handle_error_and_jsonify } from '../errors.js';
import {
handle_action_json_request,
Expand Down Expand Up @@ -122,10 +122,7 @@ export async function render_page(
// renders an empty 'shell' page if SSR is turned off and if there is
// no server data to prerender. As a result, the load functions and rendering
// only occur client-side.
if (
ssr === false &&
!((state.prerendering || state.prerender_default === true) && should_prerender_data)
) {
if (ssr === false && !(renders_prerendered_output(state) && should_prerender_data)) {
// if the user makes a request through a non-enhanced form, the returned value is lost
// because there is no SSR or client-side handling of the response
if (DEV && action_result && !event.request.headers.has('x-sveltekit-action')) {
Expand Down Expand Up @@ -176,7 +173,7 @@ export async function render_page(

const data_serializer = server_data_serializer(event, event_state, options);
const data_serializer_json =
(state.prerendering || state.prerender_default === true) && should_prerender_data
renders_prerendered_output(state) && should_prerender_data
? server_data_serializer_json(event, event_state, options)
: null;

Expand Down
4 changes: 2 additions & 2 deletions packages/kit/src/runtime/server/page/load_data.js
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ import { with_request_store, merge_tracing } from '@sveltejs/kit/internal/server
import { record_span } from '../../telemetry/record_span.js';
import { base64_encode } from '../../utils.js';
import { NULL_BODY_STATUS } from '../constants.js';
import { get_node_type } from '../utils.js';
import { get_node_type, renders_prerendered_output } from '../utils.js';

/**
* Calls the user's server `load` function.
Expand Down Expand Up @@ -67,7 +67,7 @@ export async function load_server_data({ event, event_state, state, node, parent
}
);

if (state.prerendering || state.prerender_default === true) {
if (renders_prerendered_output(state)) {
disable_search(url);
}

Expand Down
20 changes: 12 additions & 8 deletions packages/kit/src/runtime/server/page/render.js
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,12 @@ import { create_server_routing_response, generate_route_object } from './server_
import { add_data_suffix, add_resolution_suffix } from '../../pathname.js';
import { try_get_request_store, with_request_store } from '@sveltejs/kit/internal/server';
import { text_encoder } from '../../utils.js';
import { count_non_ssi_comments, create_replacer, get_global_name } from '../utils.js';
import {
count_non_ssi_comments,
create_replacer,
get_global_name,
renders_prerendered_output
} from '../utils.js';
import { handle_error_and_jsonify } from '../errors.js';
import * as env from '__sveltekit/env';
import { collect_remote_data } from '../remote-functions.js';
Expand Down Expand Up @@ -58,7 +63,7 @@ export async function render_response({
data_serializer,
error_components
}) {
if (state.prerendering || state.prerender_default === true) {
if (renders_prerendered_output(state)) {
if (options.csp.mode === 'nonce') {
throw new Error('Cannot use prerendering if config.csp.mode === "nonce"');
}
Expand Down Expand Up @@ -106,7 +111,7 @@ export async function render_response({
let base_expression = s(paths.base);

const csp = new Csp(options.csp, {
prerender: !!(state.prerendering || state.prerender_default === true)
prerender: renders_prerendered_output(state)
});

// if appropriate, use relative paths for greater portability
Expand Down Expand Up @@ -310,7 +315,7 @@ export async function render_response({
* @param {string[]} attributes
*/
const add_preload = (path, attributes) => {
if (options.link_header_preload && !(state.prerendering || state.prerender_default === true)) {
if (options.link_header_preload && !renders_prerendered_output(state)) {
link_headers.add(`<${encodeURI(path)}>; ${attributes.join('; ')}; nopush`);
} else {
head.add_link_tag(path, attributes);
Expand Down Expand Up @@ -354,7 +359,7 @@ export async function render_response({
serialize_data(
item,
resolve_opts.filterSerializedResponseHeaders,
!!(state.prerendering || state.prerender_default === true)
renders_prerendered_output(state)
)
)
.join('\n\t\t\t')}`;
Expand All @@ -367,8 +372,7 @@ export async function render_response({
// import the env.js module so that it evaluates before any user code can evaluate.
// TODO revert to using top-level await once https://bugs.webkit.org/show_bug.cgi?id=242740 is fixed
// https://github.com/sveltejs/kit/pull/11601
const load_env_eagerly =
client.uses_env_dynamic_public && (state.prerendering || state.prerender_default === true);
const load_env_eagerly = client.uses_env_dynamic_public && renders_prerendered_output(state);

if (load_env_eagerly) {
modulepreloads.add(`${paths.app_dir}/env.js`);
Expand Down Expand Up @@ -573,7 +577,7 @@ export async function render_response({
'content-type': 'text/html'
});

if (state.prerendering || state.prerender_default === true) {
if (renders_prerendered_output(state)) {
// TODO read headers set with setHeaders and convert into http-equiv where possible
const csp_headers = csp.csp_provider.get_meta();
if (csp_headers) {
Expand Down
4 changes: 3 additions & 1 deletion packages/kit/src/runtime/server/respond.js
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Original file line number Diff line number Diff line change
Expand Up @@ -435,7 +435,9 @@ export async function internal_respond(request, options, manifest, state) {
prerender = node.prerender ?? prerender;
} else if (page_nodes) {
config = page_nodes.get_config() ?? config;
prerender = state.prerender_default = page_nodes.prerender();
prerender = page_nodes.prerender();
// data requests never reach render_page, so this assignment is what covers them
state.prerender_default = prerender;
}

if (state.emulator?.platform) {
Expand Down
11 changes: 11 additions & 0 deletions packages/kit/src/runtime/server/utils.js
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Original file line number Diff line number Diff line change
Expand Up @@ -140,6 +140,17 @@ export function count_non_ssi_comments(str) {
return (str.match(/<!--(?!#)/g) ?? []).length;
}

/**
* Whether the response should be rendered as prerendered output, either because we're
* inside the prerendering pass at build time or because the page is prerenderable
* and dev output should match the build
* @param {import('types').SSRState} state
* @returns {boolean}
*/
export function renders_prerendered_output(state) {
return !!state.prerendering || (__SVELTEKIT_DEV__ && state.prerender_default === true);
}

/**
* Creates a serialiser for non-arbitrary POJOs using the app's transport hook
* @param {ServerHooks['transport']} transport
Expand Down
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