Merge pull request #1081 from joshunrau/patches

add new `__import` wrapper to internal instrument bundle implementation

Author: joshunrau

packages/instrument-bundler/src/__tests__/transform.test.ts

@@ -1,28 +1,26 @@
 import { describe, expect, it } from 'vitest';
 
-import { transformStaticImports } from '../transform.js';
+import { transformImports } from '../transform.js';
 
-describe('transformStaticImports', () => {
+describe('transformImports', () => {
   it('should transform a default import', () => {
-    expect(transformStaticImports("import React from 'react';")).toBe(
-      "const { default: React } = await import('react');"
-    );
+    expect(transformImports("import React from 'react';")).toBe("const { default: React } = await import('react');");
   });
   it('should transform named imports', () => {
-    expect(transformStaticImports("import { useEffect, useState } from 'react';")).toBe(
+    expect(transformImports("import { useEffect, useState } from 'react';")).toBe(
       "const { useEffect, useState } = await import('react');"
     );
   });
   it('should transform named and default imports from the same source', () => {
-    expect(transformStaticImports("import React, { useState } from 'react';")).toBe(
+    expect(transformImports("import React, { useState } from 'react';")).toBe(
       "const { useState, default: React } = await import('react');"
     );
   });
   it('should transform a namespace import', () => {
-    expect(transformStaticImports("import * as React from 'react';")).toBe("const React = await import('react');");
+    expect(transformImports("import * as React from 'react';")).toBe("const React = await import('react');");
   });
   it('should transform named and default imports from the same source', () => {
-    expect(transformStaticImports("import _ from 'lodash'; import { useEffect, useState } from 'react';")).toBe(
+    expect(transformImports("import _ from 'lodash'; import { useEffect, useState } from 'react';")).toBe(
       "const { default: _ } = await import('lodash'); const { useEffect, useState } = await import('react');"
     );
   });

packages/instrument-bundler/src/bundle.ts

@@ -1,12 +1,19 @@
 import { build } from './build.js';
 import { preprocess } from './preprocess.js';
-import { transformStaticImports } from './transform.js';
+import { transformImports } from './transform.js';
 import * as esbuild from './vendor/esbuild.js';
 
 import type { BundleOptions } from './schemas.js';
 import type { BuildOutput } from './types.js';
 
-const GLOBAL_PROXY_SHIM = `
+const GLOBALS = `
+  globalThis.__import = async (moduleName) => {
+    try {
+      return import(moduleName);
+    } catch (err) {
+      throw new Error('Failed to import module: ' + moduleName, { cause: err });
+    }
+  };
   const __createProxy = (name) => {
     const formatErrorMessage = (method, propertyName, targetName) => {
       const contextName = globalThis.__ODC_BUNDLER_ERROR_CONTEXT ?? 'UNKNOWN'
@@ -39,7 +46,7 @@ export async function createBundle(output: BuildOutput, options: { minify: boole
     inject = `Object.defineProperty(__exports.content, '__injectHead', { value: Object.freeze({ style: "${btoa(output.css)}" }), writable: false });`;
   }
   const bundle = `(async () => {
-    ${GLOBAL_PROXY_SHIM}
+    ${GLOBALS}
     ${output.js}
     ${inject}
     return __exports;
@@ -60,6 +67,6 @@ export async function createBundle(output: BuildOutput, options: { minify: boole
 export async function bundle({ inputs, minify = true }: BundleOptions): Promise<string> {
   preprocess(inputs);
   const result = await build({ inputs });
-  result.js = transformStaticImports(result.js);
+  result.js = transformImports(result.js);
   return createBundle(result, { minify });
 }

packages/instrument-bundler/src/transform.ts

@@ -18,7 +18,7 @@ function transformImportClause(importClause: ImportClause) {
   return `{ ${names.join(', ')} }`;
 }
 
-export function transformStaticImports(code: string) {
+export function transformImports(code: string) {
   let indexDiff = 0;
   for (const {
     endIndex: _endIndex,
@@ -33,7 +33,7 @@ export function transformStaticImports(code: string) {
     const endIndex = _endIndex + indexDiff;
     const startIndex = _startIndex + indexDiff;
     const source = code.slice(startIndex, endIndex);
-    const replacement = `const ${transformImportClause(importClause!)} = await import(${moduleSpecifier.code})`;
+    const replacement = `const ${transformImportClause(importClause!)} = await __import(${moduleSpecifier.code})`;
     indexDiff += replacement.length - source.length;
     code = code.slice(0, startIndex) + replacement + code.slice(endIndex, code.length);
   }