diff --git a/packages/astro/src/assets/utils/transformToPath.ts b/packages/astro/src/assets/utils/transformToPath.ts
index 41f33aed8536..54872a73460a 100644
--- a/packages/astro/src/assets/utils/transformToPath.ts
+++ b/packages/astro/src/assets/utils/transformToPath.ts
@@ -36,12 +36,13 @@ export function hashTransform(
 }
 
 export function getAssetsPrefix(fileType: string, assetsPrefix?: AssetsPrefix):string {
-	if (!assetsPrefix) return ''
-	if (typeof assetsPrefix === 'string') return assetsPrefix
+	if (!assetsPrefix) return '';
+	if (typeof assetsPrefix === 'string') return assetsPrefix;
+	fileType = fileType[0] === '.' ? fileType.slice(1) : fileType;
 	if (assetsPrefix[fileType]) {
-		return assetsPrefix[fileType]
+		return assetsPrefix[fileType];
 	} else if (assetsPrefix.defaultAssetsPrefix) {
-		return assetsPrefix.defaultAssetsPrefix
+		return assetsPrefix.defaultAssetsPrefix;
 	}
-	return ''
+	return '';
 }
\ No newline at end of file
diff --git a/packages/astro/src/core/create-vite.ts b/packages/astro/src/core/create-vite.ts
index 275cb09cc573..56c2711f7a42 100644
--- a/packages/astro/src/core/create-vite.ts
+++ b/packages/astro/src/core/create-vite.ts
@@ -35,6 +35,7 @@ import { createViteLogger } from './logger/vite.js';
 import { vitePluginMiddleware } from './middleware/vite-plugin.js';
 import { joinPaths } from './path.js';
 import { getAssetsPrefix } from '../assets/utils/transformToPath.js';
+import { isObject } from './util.js';
 
 interface CreateViteOptions {
 	settings: AstroSettings;
@@ -311,5 +312,5 @@ function isCommonNotAstro(dep: string): boolean {
 }
 
 function stringifyForDefine(value: string | undefined | object): string {
-	return typeof value === 'string' ? JSON.stringify(value) : 'undefined';
+	return (typeof value === "string" || isObject(value)) ? JSON.stringify(value) : "undefined";
 }
diff --git a/packages/astro/test/astro-assets-prefix-mult-cdn.test.js b/packages/astro/test/astro-assets-prefix-mult-cdn.test.js
index 14ef1d7e34bd..dd412deba0cc 100644
--- a/packages/astro/test/astro-assets-prefix-mult-cdn.test.js
+++ b/packages/astro/test/astro-assets-prefix-mult-cdn.test.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import testAdapter from './test-adapter.js';
 import { loadFixture } from './test-utils.js';
@@ -34,7 +35,7 @@ describe('Assets Prefix Multiple CDN - Static', () => {
 		const $ = cheerio.load(html);
 		const stylesheets = $('link[rel="stylesheet"]');
 		stylesheets.each((i, el) => {
-			expect(el.attribs.href).to.match(cssAssetsPrefixRegex);
+			assert.match(el.attribs.href, cssAssetsPrefixRegex)
 		});
 	});
 
@@ -42,40 +43,39 @@ describe('Assets Prefix Multiple CDN - Static', () => {
 		const html = await fixture.readFile('/index.html');
 		const $ = cheerio.load(html);
 		const imgAsset = $('#image-asset');
-		expect(imgAsset.attr('src')).to.match(defaultAssetsPrefixRegex);
+		assert.match(imgAsset.attr('src'), defaultAssetsPrefixRegex);
 	});
 
 	it('react component astro-island should import from jsAssetsPrefix', async () => {
 		const html = await fixture.readFile('/index.html');
 		const $ = cheerio.load(html);
 		const island = $('astro-island');
-		expect(island.attr('component-url')).to.match(jsAssetsPrefixRegex);
-		expect(island.attr('renderer-url')).to.match(jsAssetsPrefixRegex);
+		assert.match(island.attr('component-url'), jsAssetsPrefixRegex);
+		assert.match(island.attr('renderer-url'), jsAssetsPrefixRegex);
 	});
 
 	it('import.meta.env.ASSETS_PREFIX works', async () => {
 		const html = await fixture.readFile('/index.html');
 		const $ = cheerio.load(html);
 		const env = $('#assets-prefix-env');
-		expect(env.text()).to.equal(JSON.stringify(assetsPrefix));
+		assert.equal(env.text(), JSON.stringify(assetsPrefix));
 	});
 
 	it('markdown image src start with assetsPrefix', async () => {
 		const html = await fixture.readFile('/markdown/index.html');
 		const $ = cheerio.load(html);
-		const imgAsset = $('img');
-		expect(imgAsset.attr('src')).to.match(defaultAssetsPrefixRegex);
+		const imgAssets = $('img');
+		assert.match(imgAssets.attr('src'), defaultAssetsPrefixRegex);
 	});
 
 	it('content collections image src start with assetsPrefix', async () => {
 		const html = await fixture.readFile('/blog/index.html');
 		const $ = cheerio.load(html);
 		const imgAsset = $('img');
-		expect(imgAsset.attr('src')).to.match(defaultAssetsPrefixRegex);
+		assert.match(imgAsset.attr('src'), defaultAssetsPrefixRegex);
 	});
 });
 
-
 describe('Assets Prefix Multiple CDN, server', () => {
 	let app;
 
@@ -95,43 +95,43 @@ describe('Assets Prefix Multiple CDN, server', () => {
 	it('all stylesheets should start with assetPrefix', async () => {
 		const request = new Request('http://example.com/custom-base/');
 		const response = await app.render(request);
-		expect(response.status).to.equal(200);
+		assert.equal(response.status, 200);
 		const html = await response.text();
 		const $ = cheerio.load(html);
 		const stylesheets = $('link[rel="stylesheet"]');
 		stylesheets.each((i, el) => {
-			expect(el.attribs.href).to.match(cssAssetsPrefixRegex);
+			assert.match(el.attribs.href, cssAssetsPrefixRegex);
 		});
 	});
 
 	it('image src start with assetsPrefix', async () => {
 		const request = new Request('http://example.com/custom-base/');
 		const response = await app.render(request);
-		expect(response.status).to.equal(200);
+		assert.equal(response.status, 200);
 		const html = await response.text();
 		const $ = cheerio.load(html);
 		const imgAsset = $('#image-asset');
-		expect(imgAsset.attr('src')).to.match(defaultAssetsPrefixRegex);
+		assert.match(imgAsset.attr('src'), defaultAssetsPrefixRegex);
 	});
 
 	it('react component astro-island should import from assetsPrefix', async () => {
 		const request = new Request('http://example.com/custom-base/');
 		const response = await app.render(request);
-		expect(response.status).to.equal(200);
+		assert.equal(response.status, 200);
 		const html = await response.text();
 		const $ = cheerio.load(html);
 		const island = $('astro-island');
-		expect(island.attr('component-url')).to.match(jsAssetsPrefixRegex);
-		expect(island.attr('renderer-url')).to.match(jsAssetsPrefixRegex);
+		assert.match(island.attr('component-url'), jsAssetsPrefixRegex);
+		assert.match(island.attr('renderer-url'), jsAssetsPrefixRegex);
 	});
 
 	it('markdown optimized image src does not start with assetsPrefix in SSR', async () => {
 		const request = new Request('http://example.com/custom-base/markdown/');
 		const response = await app.render(request);
-		expect(response.status).to.equal(200);
+		assert.equal(response.status, 200);
 		const html = await response.text();
 		const $ = cheerio.load(html);
 		const imgAsset = $('img');
-		expect(imgAsset.attr('src')).to.not.match(defaultAssetsPrefixRegex);
+		assert.doesNotMatch(imgAsset.attr('src'), defaultAssetsPrefixRegex);
 	});
 });
diff --git a/packages/astro/test/fixtures/astro-assets-prefix/src/pages/index.astro b/packages/astro/test/fixtures/astro-assets-prefix/src/pages/index.astro
index 67f6e97fa56c..4158153205f4 100644
--- a/packages/astro/test/fixtures/astro-assets-prefix/src/pages/index.astro
+++ b/packages/astro/test/fixtures/astro-assets-prefix/src/pages/index.astro
@@ -13,7 +13,7 @@ import Counter from '../components/Counter.jsx';
     <img id="image-asset" src={p1Image.src} width={p1Image.width} height={p1Image.height} alt="penguin" />
     <Image src={p1Image} alt="penguin" />
     <Counter client:load />
-    <p id="assets-prefix-env">{import.meta.env.ASSETS_PREFIX}</p>
+    <p id="assets-prefix-env">{typeof import.meta.env.ASSETS_PREFIX === 'string' ? import.meta.env.ASSETS_PREFIX : JSON.stringify(import.meta.env.ASSETS_PREFIX)}</p>
     <style>
       h1 {
         color: red;