[Next] fetch support (#1563)

* fix: polyfill fetch in every ssr scenario

* test(fetch): update fetch tests

* docs: update data fetching guide to remove caveats about `fetch` and isomorphic usage

* refactor: update regex for clarity

docs/src/pages/guides/data-fetching.md

@@ -32,11 +32,10 @@ console.log(data);
 
 ## Using `fetch()` outside of Astro Components
 
-If you want to use `fetch()` in a non-astro component, use the [`node-fetch`](https://github.com/node-fetch/node-fetch) library:
+If you want to use `fetch()` in a non-astro component, it is also globally available:
 
 ```tsx
 // Movies.tsx
-import fetch from 'node-fetch';
 import type { FunctionalComponent } from 'preact';
 import { h } from 'preact';
 
@@ -55,11 +54,3 @@ const Movies: FunctionalComponent = () => {
 
 export default Movies;
 ```
-
-If you load a component using `node-fetch` [interactively](/core-concepts/component-hydration), with `client:load`, `client:visible`, etc., you'll need to either not use `node-fetch` or switch to an [isomorphic](https://en.wikipedia.org/wiki/Isomorphic_JavaScript) library that will run both at build time and on the client, as the [`node-fetch` README.md](https://github.com/node-fetch/node-fetch#motivation) recommends:
-
-> Instead of implementing XMLHttpRequest in Node.js to run browser-specific [Fetch polyfill](https://github.com/github/fetch), why not go from native http to fetch API directly? Hence, node-fetch, minimal code for a window.fetch compatible API on Node.js runtime.
->
-> See Jason Miller's [isomorphic-unfetch](https://www.npmjs.com/package/isomorphic-unfetch) or Leonardo Quixada's [cross-fetch](https://github.com/lquixada/cross-fetch) for isomorphic usage (exports node-fetch for server-side, whatwg-fetch for client-side).
-
-> Quoted from https://github.com/node-fetch/node-fetch#motivation

packages/astro/src/runtime/vite/config.ts

@@ -11,6 +11,7 @@ import astroVitePlugin from './plugin-astro.js';
 import astroPostprocessVitePlugin from './plugin-astro-postprocess.js';
 import markdownVitePlugin from './plugin-markdown.js';
 import jsxVitePlugin from './plugin-jsx.js';
+import fetchVitePlugin from './plugin-fetch.js';
 import { AstroDevServer } from '../../dev';
 
 const require = createRequire(import.meta.url);
@@ -86,6 +87,7 @@ export async function loadViteConfig(
         markdownVitePlugin({ config: astroConfig, devServer }), 
         jsxVitePlugin({ config: astroConfig, logging }), 
         astroPostprocessVitePlugin({ config: astroConfig, devServer }),
+        fetchVitePlugin(),
         ...plugins
       ],
       publicDir: fileURLToPath(astroConfig.public),

packages/astro/src/runtime/vite/plugin-fetch.ts

@@ -0,0 +1,58 @@
+import type { Plugin } from 'vite';
+import MagicString from 'magic-string';
+
+// https://github.com/vitejs/vite/discussions/5109#discussioncomment-1450726
+function isSSR(options: undefined | boolean | { ssr: boolean }): boolean {
+  if (options === undefined) {
+    return false
+  }
+  if (typeof options === 'boolean') {
+    return options
+  }
+  if (typeof options == 'object') {
+    return !!options.ssr
+  }
+  return false
+}
+
+// This matches any JS-like file (that we know of)
+// See https://regex101.com/r/Cgofir/1
+const SUPPORTED_FILES = /\.(astro|svelte|vue|[cm]?js|jsx|[cm]?ts|tsx)$/;
+const DEFINE_FETCH = `import fetch from 'node-fetch';\n`;
+
+export default function pluginFetch(): Plugin {
+  return {
+    name: '@astrojs/vite-plugin-fetch',
+    enforce: 'post',
+    async transform(code, id, opts) {
+      const ssr = isSSR(opts);
+      
+      // If this isn't an SSR pass, `fetch` will already be available!
+      if (!ssr) {
+        return null;
+      }
+      
+      // Only transform JS-like files
+      if (!id.match(SUPPORTED_FILES)) {
+        return null;
+      }
+      
+      // Optimization: only run on probable matches
+      if (!code.includes('fetch')) {
+        return null;
+      }
+      
+      const s = new MagicString(code);
+      s.prepend(DEFINE_FETCH);
+
+      const result = s.toString();
+
+      const map = s.generateMap({
+        source: id,
+        includeContent: true
+      });
+      
+      return { code: result, map }
+    },
+  };
+}

packages/astro/test/fetch.test.js

@@ -1,5 +1,3 @@
-/**
- * UNCOMMENT: add fetch() in component support
 import { expect } from 'chai';
 import cheerio from 'cheerio';
 import { loadFixture } from './test-utils.js';
@@ -11,14 +9,22 @@ before(async () => {
   await fixture.build();
 });
 
-
 describe('Global Fetch', () => {
-  it('Is available in non-Astro components.', async () => {
+  it('Is available in Astro pages', async () => {
     const html = await fixture.readFile('/index.html');
     const $ = cheerio.load(html);
-    expect($('#jsx').text()).to.equal('function');
+    expect($('#astro-page').text()).to.equal('function', 'Fetch supported in .astro page');
+  });
+  it('Is available in Astro components', async () => {
+    const html = await fixture.readFile('/index.html');
+    const $ = cheerio.load(html);
+    expect($('#astro-component').text()).to.equal('function', 'Fetch supported in .astro components');
+  });
+  it('Is available in non-Astro components', async () => {
+    const html = await fixture.readFile('/index.html');
+    const $ = cheerio.load(html);
+    expect($('#jsx').text()).to.equal('function', 'Fetch supported in .jsx');
+    expect($('#svelte').text()).to.equal('function', 'Fetch supported in .svelte');
+    expect($('#vue').text()).to.equal('function', 'Fetch supported in .vue');
   });
 });
-*/
-
-it.skip('is skipped', () => {});

packages/astro/test/fixtures/fetch/src/components/AstroComponent.astro

@@ -0,0 +1 @@
+<span id="astro-component">{typeof fetch}</span>

packages/astro/test/fixtures/fetch/src/components/SvelteComponent.svelte

@@ -0,0 +1 @@
+<span id="svelte">{ typeof fetch }</span>

packages/astro/test/fixtures/fetch/src/components/VueComponent.vue

@@ -0,0 +1,16 @@
+<template>
+  <span id="vue">{{ type }}</span>
+</template>
+
+<script>
+import { defineComponent } from 'vue'
+
+export default defineComponent({
+  setup() {
+    return {
+      type: typeof fetch
+    }
+  }
+})
+</script>
+

packages/astro/test/fixtures/fetch/src/pages/index.astro

@@ -1,5 +1,8 @@
 ---
-import Child from '../components/Child.jsx';
+import Test from '../components/AstroComponent.astro';
+import JsxComponent from '../components/JsxComponent.jsx';
+import SvelteComponent from '../components/SvelteComponent.svelte';
+import VueComponent from '../components/VueComponent.vue';
 ---
 
 <html lang="en">
@@ -7,6 +10,10 @@ import Child from '../components/Child.jsx';
   <title>Global fetch</title>
 </head>
 <body>
-  <Child />
+  <span id="astro-page">{typeof fetch}</span>
+  <Test />
+  <JsxComponent />
+  <SvelteComponent />
+  <VueComponent />
 </body>
 </html>