feat: support npm resolution for file imports

.changeset/long-starfishes-mate.md

@@ -0,0 +1,19 @@
+---
+"wrangler": minor
+---
+
+feat: resolve npm exports for file imports
+
+Previously, when using wasm (or other static files) from an npm package, you would have to import the file like so:
+
+```js
+import wasm from "../../node_modules/svg2png-wasm/svg2png_wasm_bg.wasm";
+```
+
+This update now allows you to import the file like so, assuming it's exposed and available in the package's `exports` field:
+
+```js
+import wasm from "svg2png-wasm/svg2png_wasm_bg.wasm";
+```
+
+This will look at the package's `exports` field in `package.json` and resolve the file using [`resolve.exports`](https://www.npmjs.com/package/resolve.exports).

fixtures/import-wasm-example/.gitignore

@@ -0,0 +1 @@
+dist

fixtures/import-wasm-example/README.md

@@ -0,0 +1,3 @@
+# import-wasm-example
+
+`import-wasm-example` is a test fixture that imports a `wasm` file from `import-wasm-static`, testing npm module resolution with wrangler imports.

fixtures/import-wasm-example/package.json

@@ -0,0 +1,23 @@
+{
+	"name": "import-wasm-example",
+	"version": "1.0.1",
+	"private": true,
+	"description": "",
+	"author": "",
+	"main": "src/index.js",
+	"scripts": {
+		"check:type": "tsc",
+		"test": "npx vitest run",
+		"test:ci": "npx vitest run",
+		"test:watch": "npx vitest",
+		"type:tests": "tsc -p ./tests/tsconfig.json"
+	},
+	"devDependencies": {
+		"undici": "^5.9.1",
+		"wrangler": "workspace:*",
+		"@cloudflare/workers-tsconfig": "workspace:^"
+	},
+	"dependencies": {
+		"import-wasm-static": "workspace:^"
+	}
+}

fixtures/import-wasm-example/src/index.js

@@ -0,0 +1,12 @@
+// this is from the `import-wasm-static` fixture defined above
+// and setup inside package.json to mimic an npm package
+import multiply from "import-wasm-static/multiply.wasm";
+
+export default {
+	async fetch(request) {
+		// just instantiate and return something
+		// we're really just testing the import at the top of this file
+		const multiplyModule = await WebAssembly.instantiate(multiply);
+		return new Response(`${multiplyModule.exports.multiply(7, 3)}`);
+	},
+};

fixtures/import-wasm-example/tests/index.test.ts

@@ -0,0 +1,25 @@
+import { resolve } from "path";
+import { fetch } from "undici";
+import { describe, it, beforeAll, afterAll } from "vitest";
+import { runWranglerDev } from "../../shared/src/run-wrangler-long-lived";
+
+describe("wrangler correctly imports wasm files with npm resolution", () => {
+	let ip: string, port: number, stop: (() => Promise<unknown>) | undefined;
+
+	beforeAll(async () => {
+		({ ip, port, stop } = await runWranglerDev(resolve(__dirname, ".."), [
+			"--port=0",
+		]));
+	});
+
+	afterAll(async () => {
+		await stop?.();
+	});
+
+	// if the worker compiles, is running, and returns 21 (7 * 3) we can assume that the wasm module was imported correctly
+	it("responds", async ({ expect }) => {
+		const response = await fetch(`http://${ip}:${port}/`);
+		const text = await response.text();
+		expect(text).toBe("21");
+	});
+});

fixtures/import-wasm-example/tests/tsconfig.json

@@ -0,0 +1,7 @@
+{
+	"extends": "@cloudflare/workers-tsconfig/tsconfig.json",
+	"compilerOptions": {
+		"types": ["node"]
+	},
+	"include": ["**/*.ts", "../../../node-types.d.ts"]
+}

fixtures/import-wasm-example/tsconfig.json

@@ -0,0 +1,12 @@
+{
+	"compilerOptions": {
+		"target": "ES2020",
+		"esModuleInterop": true,
+		"module": "CommonJS",
+		"lib": ["ES2020"],
+		"types": ["node"],
+		"moduleResolution": "node",
+		"noEmit": true
+	},
+	"include": ["tests", "../../node-types.d.ts"]
+}

fixtures/import-wasm-example/wrangler.toml

@@ -0,0 +1,4 @@
+name = "import-wasm-example"
+compatibility_date = "2023-10-02"
+
+main = "src/index.js"

fixtures/import-wasm-static/README.md

@@ -0,0 +1,3 @@
+# import-wasm-static
+
+`import-wasm-static` is a fixture that simply exports a `wasm` file via `package.json` exports to be used and imported in other fixtures, to test npm module resolution.

fixtures/import-wasm-static/package.json

@@ -0,0 +1,9 @@
+{
+	"name": "import-wasm-static",
+	"version": "0.0.1",
+	"private": true,
+	"sideEffects": false,
+	"exports": {
+		"./multiply.wasm": "./wasm/multiply.wasm"
+	}
+}

fixtures/import-wasm-static/wasm/multiply.wat

@@ -0,0 +1,7 @@
+(module
+  (func $multiply (param $p1 i32) (param $p2 i32) (result i32)
+    local.get $p1
+    local.get $p2
+    i32.mul)
+  (export "multiply" (func $multiply))
+)

packages/wrangler/package.json

@@ -110,6 +110,7 @@
 		"miniflare": "3.20231016.0",
 		"nanoid": "^3.3.3",
 		"path-to-regexp": "^6.2.0",
+		"resolve.exports": "^2.0.2",
 		"selfsigned": "^2.0.1",
 		"source-map": "0.6.1",
 		"source-map-support": "0.5.21",

packages/wrangler/src/__tests__/module-collection.test.ts

@@ -0,0 +1,20 @@
+import { extractPackageName } from "../deployment-bundle/module-collection";
+
+describe("Module Collection", () => {
+	describe("extractPackageName", () => {
+		test.each`
+			importString                           | packageName
+			${"wrangler"}                          | ${"wrangler"}
+			${"wrangler/example"}                  | ${"wrangler"}
+			${"wrangler/example.wasm"}             | ${"wrangler"}
+			${"@cloudflare/wrangler"}              | ${"@cloudflare/wrangler"}
+			${"@cloudflare/wrangler/example"}      | ${"@cloudflare/wrangler"}
+			${"@cloudflare/wrangler/example.wasm"} | ${"@cloudflare/wrangler"}
+			${"./some/file"}                       | ${null}
+			${"../some/file"}                      | ${null}
+			${"/some/file"}                        | ${null}
+		`("$importString --> $packageName", ({ importString, packageName }) => {
+			expect(extractPackageName(importString)).toBe(packageName);
+		});
+	});
+});

packages/wrangler/src/deployment-bundle/bundle.ts

@@ -31,6 +31,9 @@ export const COMMON_ESBUILD_OPTIONS = {
 	loader: { ".js": "jsx", ".mjs": "jsx", ".cjs": "jsx" },
 } as const;
 
+// build conditions used by esbuild, and when resolving custom `import` calls
+export const BUILD_CONDITIONS = ["workerd", "worker", "browser"];
+
 /**
  * Information about Wrangler's bundling process that needs passed through
  * for DevTools sourcemap transformation
@@ -310,7 +313,7 @@ export async function bundleWorker(
 		sourceRoot: destination,
 		minify,
 		metafile: true,
-		conditions: ["workerd", "worker", "browser"],
+		conditions: BUILD_CONDITIONS,
 		...(process.env.NODE_ENV && {
 			define: {
 				// use process.env["NODE_ENV" + ""] so that esbuild doesn't replace it

packages/wrangler/src/deployment-bundle/module-collection.ts

@@ -3,7 +3,9 @@
 import { readFile } from "node:fs/promises";
 import path from "node:path";
 import globToRegExp from "glob-to-regexp";
+import { exports as resolveExports } from "resolve.exports";
 import { logger } from "../logger";
+import { BUILD_CONDITIONS } from "./bundle";
 import {
 	findAdditionalModules,
 	findAdditionalModuleWatchDirs,
@@ -64,6 +66,23 @@
 	},
 };
 
+// Extracts a package name from a string that may be a file path
+// or a package name. Returns null if the string is not a valid
+// Handles `wrangler`, `wrangler/example`, `wrangler/example.wasm`,
+// `@cloudflare/wrangler`, `@cloudflare/wrangler/example`, etc.
+export function extractPackageName(packagePath: string) {
+	if (packagePath.startsWith(".")) return null;
+
+	const match = packagePath.match(/^(@[^/]+\/)?([^/]+)/);
+
+	if (match) {
+		const scoped = match[1] || "";
+		const packageName = match[2];
+		return `${scoped}${packageName}`;
+	}
+	return null;
+}
+
 export function createModuleCollector(props: {
 	entry: Entry;
 	findAdditionalModules: boolean;
@@ -237,7 +256,7 @@
 								// take the file and massage it to a
 								// transportable/manageable format
 
-								const filePath = path.join(args.resolveDir, args.path);
+								let filePath = path.join(args.resolveDir, args.path);
 
 								// If this was a found additional module, mark it as external.
 								// Note, there's no need to watch the file here as we already
@@ -251,6 +270,51 @@
 								// it to `esbuild` to bundle it.
 								if (isJavaScriptModuleRule(rule)) return;
 
+								// Check if this file is possibly from an npm package
+								// and if so, validate the import against the package.json exports
+								// and resolve the file path to the correct file.
+								if (args.path.includes("/") && !args.path.startsWith(".")) {
+									// get npm package name from string, taking into account scoped packages
+									const packageName = extractPackageName(args.path);
+									if (!packageName) {
+										throw new Error(
+											`Unable to extract npm package name from ${args.path}`
+										);
+									}
+									const packageJsonPath = path.join(
+										process.cwd(),
+										"node_modules",
+										packageName,
+										"package.json"
+									);
+									// Try and read the npm package's package.json
+									// and then resolve the import against the package's exports
+									// and then finally override filePath if we find a match.
+									try {
+										const packageJson = JSON.parse(
+											await readFile(packageJsonPath, "utf8")
+										);
+										const testResolved = resolveExports(
+											packageJson,
+											args.path.replace(`${packageName}/`, ""),
+											{
+												conditions: BUILD_CONDITIONS,
+											}
+										);
+										if (testResolved) {
+											filePath = path.join(
+												process.cwd(),
+												"node_modules",
+												packageName,
+												testResolved[0]
+											);
+										}
+									} catch (e) {
+										// We tried, now it'll just fall-through to the previous behaviour
+										// and ENOENT if the absolute file path doesn't exist.
+									}
+								}
+
 								const fileContent = await readFile(filePath);
 								const fileHash = crypto
 									.createHash("sha1")