Use a babel plugin in order to strip /src/ from the import paths

external/builder/babel-plugin-pdfjs-preprocessor.mjs

@@ -292,6 +292,20 @@ function babelPluginPDFJSPreprocessor(babel, ctx) {
   };
 }
 
+function babelPluginStripSrcPath() {
+  return {
+    name: "babel-plugin-strip-src-path",
+    visitor: {
+      "ImportDeclaration|ExportNamedDeclaration|ExportAllDeclaration":
+        function ({ node }) {
+          if (node.source?.value.includes("/src/")) {
+            node.source.value = node.source.value.replace("/src/", "/");
+          }
+        },
+    },
+  };
+}
+
 function preprocessPDFJSCode(ctx, content) {
   return transformSync(content, {
     configFile: false,
@@ -299,4 +313,8 @@ function preprocessPDFJSCode(ctx, content) {
   }).code;
 }
 
-export { babelPluginPDFJSPreprocessor, preprocessPDFJSCode };
+export {
+  babelPluginPDFJSPreprocessor,
+  babelPluginStripSrcPath,
+  preprocessPDFJSCode,
+};

gulpfile.mjs

@@ -15,6 +15,7 @@
 
 import {
   babelPluginPDFJSPreprocessor,
+  babelPluginStripSrcPath,
   preprocessPDFJSCode,
 } from "./external/builder/babel-plugin-pdfjs-preprocessor.mjs";
 import { exec, execSync, spawn, spawnSync } from "child_process";
@@ -1592,6 +1593,7 @@ function buildLibHelper(bundleDefines, inputStream, outputDir) {
             ],
         plugins: [
           [babelPluginPDFJSPreprocessor, ctx],
+          [babelPluginStripSrcPath],
           [
             "add-header-comment",
             {
@@ -1604,13 +1606,7 @@ function buildLibHelper(bundleDefines, inputStream, outputDir) {
         sourceFileName: relativeSourcePath,
       });
 
-      let code = result.code;
+      file.contents = Buffer.from(result.code);
-      code = code.replaceAll(
-        /(\sfrom\s".*?)(?:\/src)(\/[^"]*"?;)$/gm,
-        (all, prefix, suffix) => prefix + suffix
-      );
-
-      file.contents = Buffer.from(code);
       // Attach the source map to the file for gulp-sourcemaps
       if (result.map) {
         file.sourceMap = result.map;