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feat: typed +server.ts responses with fetch #11108

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9e03447
api_fetch module declaration initial
AlbertMarashi Nov 23, 2023
21b15e4
Fix tests
AlbertMarashi Nov 23, 2023
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66 changes: 57 additions & 9 deletions packages/kit/src/core/sync/write_types/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ import MagicString from 'magic-string';
import { posixify, rimraf, walk } from '../../../utils/filesystem.js';
import { compact } from '../../../utils/array.js';
import { ts } from '../ts.js';
import { dedent } from '../utils.js';

/**
* @typedef {{
Expand Down Expand Up @@ -335,7 +336,41 @@ function update_types(config, routes, route, to_delete = new Set()) {
}

if (route.endpoint) {
// get the from/to for the proxy
const from = path_to_original(outdir, route.endpoint.file);
// We have to find out which methods are available/exported on the endpoint.
const proxy = createProxy(route.endpoint.file, 'endpoint');

if(proxy) {
// For each exported method, we create a type that represents the function signature.
exports.push('export type APIReturnType<T = any> = T extends (...args: any[]) => Promise<TypedResponse<infer O>> ? Promise<O> : never;');

exports.push(dedent`
declare module '$api' {
${proxy.exports.map((method) => dedent`
export function api_fetch(
url: RouteId,
options: FetchOptions<RouteParams, "${method}">
): APIReturnType<typeof import('${from}').${method}>;`
).join('\n')}
}`);
}


exports.push('export type RequestHandler = Kit.RequestHandler<RouteParams, RouteId>;');
exports.push(dedent`
interface TypedResponse<O> extends Response {
json(): Promise<O>;
}
type Methods = "GET" | "POST" | "PUT" | "DELETE" | "HEAD" | "OPTIONS" | "PATCH";
type FetchOptions<
Params = never,
Method extends Methods = Methods
> = Parameters<typeof fetch>[1] & {
params: Params,
method: Method
}
`)
}

if (route.leaf?.server || route.layout?.server || route.endpoint) {
Expand Down Expand Up @@ -502,21 +537,21 @@ function process_node(node, outdir, is_page, proxies, all_pages_have_load = true
*/
function ensureProxies(node, proxies) {
if (node.server && !proxies.server) {
proxies.server = createProxy(node.server, true);
proxies.server = createProxy(node.server, 'page.server');
}

if (node.universal && !proxies.universal) {
proxies.universal = createProxy(node.universal, false);
proxies.universal = createProxy(node.universal, 'page');
}
}

/**
* @param {string} file_path
* @param {boolean} is_server
* @param {"page.server" | "page" | "endpoint"} type
* @returns {Proxy}
*/
function createProxy(file_path, is_server) {
const proxy = tweak_types(fs.readFileSync(file_path, 'utf8'), is_server);
function createProxy(file_path, type) {
const proxy = tweak_types(fs.readFileSync(file_path, 'utf8'), type);
if (proxy) {
return {
...proxy,
Expand Down Expand Up @@ -600,11 +635,24 @@ function generate_params_type(params, outdir, config) {

/**
* @param {string} content
* @param {boolean} is_server
* @param {"page" | "page.server" | "endpoint"} type
* @returns {Omit<NonNullable<Proxy>, 'file_name'> | null}
*/
export function tweak_types(content, is_server) {
const names = new Set(is_server ? ['load', 'actions'] : ['load']);
export function tweak_types(content, type) {
/** @type {Set<string>} */
let names;

switch (type) {
case 'page.server':
names = new Set(['load', 'actions']);
break;
case 'page':
names = new Set(['load']);
break;
case 'endpoint':
names = new Set(['GET', 'POST', 'PUT', 'DELETE', 'HEAD', 'OPTIONS', 'PATCH']);
break;
}

try {
let modified = false;
Expand Down Expand Up @@ -754,7 +802,7 @@ export function tweak_types(content, is_server) {
modified = true;
}
} else if (
is_server &&
type === 'page.server' &&
ts.isIdentifier(declaration.name) &&
declaration.name?.text === 'actions' &&
declaration.initializer
Expand Down
18 changes: 9 additions & 9 deletions packages/kit/src/core/sync/write_types/index.spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ test('Rewrites types for a TypeScript module', () => {
};
`;

const rewritten = tweak_types(source, false);
const rewritten = tweak_types(source, 'page');

expect(rewritten?.exports).toEqual(['load']);
assert.equal(
Expand All @@ -83,7 +83,7 @@ test('Rewrites types for a TypeScript module without param', () => {
};
`;

const rewritten = tweak_types(source, false);
const rewritten = tweak_types(source, 'page');

expect(rewritten?.exports).toEqual(['load']);
assert.equal(
Expand All @@ -109,7 +109,7 @@ test('Rewrites types for a TypeScript module without param and jsdoc without typ
};
`;

const rewritten = tweak_types(source, false);
const rewritten = tweak_types(source, 'page');

expect(rewritten?.exports).toEqual(['load']);
assert.equal(
Expand All @@ -136,7 +136,7 @@ test('Rewrites types for a JavaScript module with `function`', () => {
};
`;

const rewritten = tweak_types(source, false);
const rewritten = tweak_types(source, 'page');

expect(rewritten?.exports).toEqual(['load']);
assert.equal(
Expand All @@ -163,7 +163,7 @@ test('Rewrites types for a JavaScript module with `const`', () => {
};
`;

const rewritten = tweak_types(source, false);
const rewritten = tweak_types(source, 'page');

expect(rewritten?.exports).toEqual(['load']);
assert.equal(
Expand All @@ -190,7 +190,7 @@ test('Appends @ts-nocheck after @ts-check', () => {
};
`;

const rewritten = tweak_types(source, false);
const rewritten = tweak_types(source, 'page');

expect(rewritten?.exports).toEqual(['load']);
assert.equal(
Expand Down Expand Up @@ -219,7 +219,7 @@ test('Rewrites action types for a JavaScript module', () => {
}
`;

const rewritten = tweak_types(source, true);
const rewritten = tweak_types(source, 'page.server');

expect(rewritten?.exports).toEqual(['actions']);
assert.equal(
Expand Down Expand Up @@ -248,7 +248,7 @@ test('Rewrites action types for a TypeScript module', () => {
}
`;

const rewritten = tweak_types(source, true);
const rewritten = tweak_types(source, 'page.server');

expect(rewritten?.exports).toEqual(['actions']);
assert.equal(
Expand Down Expand Up @@ -281,7 +281,7 @@ test('Leaves satisfies operator untouched', () => {
} satisfies Actions
`;

const rewritten = tweak_types(source, true);
const rewritten = tweak_types(source, 'page.server');

expect(rewritten?.exports).toEqual(['load', 'actions']);
assert.equal(rewritten?.modified, false);
Expand Down
14 changes: 14 additions & 0 deletions packages/kit/test/apps/basics/src/routes/endpoint-typing/foo/+server.ts
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Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
import { json } from '@sveltejs/kit';

interface TypedResponse<A> extends Response {
json(): Promise<A>;
}

// A typed json wrapper (this could probably just replace `json`
function typed_json<A>(data: A): TypedResponse<A> {
return json(data)
}

export async function GET(): Promise<TypedResponse<{ foo: string }>> {
return typed_json({ foo: 'bar' })
}