Fix ESM build issues with TSC

package.json

@@ -34,7 +34,7 @@
   },
   "scripts": {
     "prepublishOnly": "yarn build",
-    "build": "yarn build:cjs && yarn build:esm",
+    "build": "rimraf dist && yarn build:cjs && yarn build:esm",
     "build:cjs": "tsc --project .",
     "build:esm": "tsc --project tsconfig.esm.json && yarn build:esm:rename",
     "build:esm:rename": "./scripts/rename-esm.sh",
@@ -54,6 +54,7 @@
     "eslint-plugin-jest": "^24.1.3",
     "eslint-plugin-node": "^11.1.0",
     "jest": "^26.4.2",
+    "rimraf": "^3.0.2",
     "ts-jest": "^26.4.0",
     "typescript": "^4.0.5"
   },

scripts/rename-esm.sh

@@ -9,5 +9,18 @@ if [[ ${RUNNER_DEBUG:-0} == 1 ]]; then
 fi
 
 for file in dist/esm/*.js; do
+  # Rename the `.js` files to `.mjs`.
   mv "$file" "${file%.js}.mjs"
+
+  # Replace the sourceMappingURL to point to the new `.mjs.map` file.
+  sourceMap=$(basename "${file%.js}.mjs.map")
+  sed -i '' "s|//# sourceMappingURL=.*\.js\.map|//# sourceMappingURL=$sourceMap|" "${file%.js}.mjs"
+done
+
+for file in dist/esm/*.js.map; do
+  # Rename the `.js.map` files to `.mjs.map`.
+  mv "$file" "${file%.js.map}.mjs.map"
+
+  # Replace the file references in the source map to point to the new `.mjs` file.
+  sed -i '' 's/\.js/\.mjs/g' "${file%.js.map}.mjs.map"
 done

tsconfig.esm.json

@@ -10,5 +10,9 @@
   },
   "include": [
     "./**/*.ts"
+  ],
+  "exclude": [
+    "node_modules",
+    "dist"
   ]
 }

tsconfig.json

@@ -9,5 +9,9 @@
   },
   "include": [
     "./**/*.ts"
+  ],
+  "exclude": [
+    "node_modules",
+    "dist"
   ]
 }