fix(esm): replace custom fix-esm.js with tsc-alias fileExtensionReplacer

Switches from the bespoke post-processor script to tsc-alias, which
handles the full range of ESM path-rewriting edge cases (barrel
re-exports, conditional imports, declaration files, dynamic imports).

- Replace `node ../../scripts/fix-esm.js dist/esm` with
  `tsc-alias -p tsconfig.esm.json` in both build:esm scripts
- Add tsc-alias ^1.8.10 to devDependencies in both modules
- Configure tsc-alias fileExtensionReplacer in both package.json files
  (rewrites relative imports in compiled output to add .js extension)
- Retire scripts/fix-esm.js (still present but no longer invoked)"

Author: harshitanand

modules/abstract-utxo/package.json

@@ -25,7 +25,7 @@
   "scripts": {
     "build": "npm run build:cjs && npm run build:esm",
     "build:cjs": "yarn tsc --build --incremental --verbose .",
-    "build:esm": "yarn tsc --project tsconfig.esm.json && node ../../scripts/fix-esm.js dist/esm",
+    "build:esm": "yarn tsc --project tsconfig.esm.json && yarn tsc-alias -p tsconfig.esm.json",
     "fmt": "prettier --write '{src,test}/**/*.{ts,js,json}'",
     "check-fmt": "prettier --check '{src,test}/**/*.{ts,js,json}'",
     "clean": "rm -rf ./dist",
@@ -59,6 +59,14 @@
       ".ts"
     ]
   },
+  "tsc-alias": {
+    "replacers": [
+      {
+        "enabled": true,
+        "file": "tsc-alias/dist/replacers/fileExtensionReplacer.js"
+      }
+    ]
+  },
   "dependencies": {
     "@bitgo/blockapis": "^1.13.4",
     "@bitgo/sdk-api": "^1.77.0",
@@ -77,7 +85,8 @@
   },
   "devDependencies": {
     "@bitgo/sdk-test": "^9.1.38",
-    "mocha": "^10.2.0"
+    "mocha": "^10.2.0",
+    "tsc-alias": "^1.8.10"
   },
   "gitHead": "18e460ddf02de2dbf13c2aa243478188fb539f0c"
 }

modules/utxo-core/package.json

@@ -47,7 +47,7 @@
   "scripts": {
     "build": "npm run build:cjs && npm run build:esm",
     "build:cjs": "yarn tsc --build --incremental --verbose .",
-    "build:esm": "yarn tsc --project tsconfig.esm.json && node ../../scripts/fix-esm.js dist/esm",
+    "build:esm": "yarn tsc --project tsconfig.esm.json && yarn tsc-alias -p tsconfig.esm.json",
     "fmt": "prettier --write .",
     "check-fmt": "prettier --check '**/*.{ts,js,json}'",
     "clean": "rm -r ./dist",
@@ -77,6 +77,14 @@
       ".ts"
     ]
   },
+  "tsc-alias": {
+    "replacers": [
+      {
+        "enabled": true,
+        "file": "tsc-alias/dist/replacers/fileExtensionReplacer.js"
+      }
+    ]
+  },
   "dependencies": {
     "@bitgo/secp256k1": "^1.11.0",
     "@bitgo/unspents": "^0.51.3",
@@ -85,5 +93,8 @@
     "bip174": "npm:@bitgo-forks/bip174@3.1.0-master.4",
     "fast-sha256": "^1.3.0"
   },
+  "devDependencies": {
+    "tsc-alias": "^1.8.10"
+  },
   "gitHead": "18e460ddf02de2dbf13c2aa243478188fb539f0c"
 }

scripts/fix-esm.js

@@ -1,53 +1,3 @@
-const fs = require('fs');
-const path = require('path');
-
-function processDir(dir) {
-  if (!fs.existsSync(dir)) return;
-  const files = fs.readdirSync(dir);
-  for (const file of files) {
-    const fullPath = path.join(dir, file);
-    if (fs.statSync(fullPath).isDirectory()) {
-      processDir(fullPath);
-    } else if (fullPath.endsWith('.js') || fullPath.endsWith('.d.ts')) {
-      let content = fs.readFileSync(fullPath, 'utf8');
-      // Regex to match import/export statements (including dynamic imports)
-      const regex = /(from\s+['"]|import\s*\(?['"]|import\s+['"])([^'"]+)(['"]\)?)/g;
-      
-      let modifiedContent = content.replace(regex, (match, p1, p2, p3) => {
-        // Skip if already has an extension or is a known standard module/bare module that doesn't need it
-        if (p2.endsWith('.js') || p2.endsWith('.json') || p2.endsWith('.cjs') || p2.endsWith('.mjs')) {
-          return match;
-        }
-
-        // Handle relative paths
-        if (p2.startsWith('.')) {
-          // If the path corresponds to a directory, it needs /index.js
-          const targetPath = path.join(path.dirname(fullPath), p2);
-          if (fs.existsSync(targetPath) && fs.statSync(targetPath).isDirectory()) {
-            return `${p1}${p2}/index.js${p3}`;
-          } else {
-            return `${p1}${p2}.js${p3}`;
-          }
-        }
-        
-        // Handle specific subpath third-party imports mentioned in the bug report
-        if (p2.startsWith('bip174/src/')) {
-          return `${p1}${p2}.js${p3}`;
-        }
-        
-        return match;
-      });
-
-      if (modifiedContent !== content) {
-        fs.writeFileSync(fullPath, modifiedContent, 'utf8');
-      }
-    }
-  }
-}
-
-const targetDir = process.argv[2];
-if (!targetDir) {
-  console.error("Usage: node fix-esm.js <directory>");
-  process.exit(1);
-}
-processDir(targetDir);
+// Retired: ESM import path rewriting is now handled by tsc-alias.
+// See modules/*/package.json build:esm scripts and the tsc-alias
+// configuration (fileExtensionReplacer) in each module's package.json.