fix: Define entry points through the exports field and use .mjs suffixed ESM imports

package.json

@@ -26,6 +26,16 @@
   },
   "main": "lib/index.js",
   "module": "lib/index.mjs",
+  "exports": {
+    "./": {
+      "require": "./lib/index.js",
+      "import": "./lib/index.mjs"
+    },
+    "./lib/use/ws": {
+      "require": "./lib/use/ws.js",
+      "import": "./lib/use/ws.mjs"
+    }
+  },
   "types": "lib/index.d.ts",
   "browser": "umd/graphql-ws.js",
   "files": [
@@ -43,7 +53,7 @@
     "lint": "eslint 'src'",
     "type-check": "tsc --noEmit",
     "test": "jest",
-    "build:esm": "tsc -b tsconfig.esm.json && find ./lib -name \"*.js\" -exec sh -c 'mv \"$0\" \"${0%.js}.mjs\"' \"{}\" \\;",
+    "build:esm": "tsc -b tsconfig.esm.json && node scripts/esm-post-process.js",
     "build:cjs": "tsc -b tsconfig.cjs.json",
     "build:umd": "rollup -c && gzip umd/graphql-ws.min.js -c > umd/graphql-ws.min.js.gz",
     "build": "yarn build:esm && yarn build:cjs && yarn build:umd",
@@ -71,9 +81,11 @@
     "eslint": "^7.19.0",
     "eslint-config-prettier": "^7.2.0",
     "eslint-plugin-prettier": "^3.3.1",
+    "glob": "^7.1.6",
     "graphql": "^15.5.0",
     "jest": "^26.6.3",
     "prettier": "^2.2.1",
+    "replacestream": "^4.0.3",
     "rollup": "^2.38.5",
     "rollup-plugin-terser": "^7.0.2",
     "semantic-release": "^17.3.8",

scripts/esm-post-process.js

@@ -0,0 +1,20 @@
+"use strict";
+
+const fs = require("fs");
+const path = require("path");
+const glob = require("glob");
+const replaceStream = require("replacestream");
+
+glob("lib/**/*.js", (_, filePaths) => {
+  for (const filePath of filePaths) {
+    const parts = filePath.split(".")
+    parts.pop();
+    const mjsFileName = parts.join(".") + ".mjs"
+    fs.createReadStream(path.join(__dirname, "..", filePath))
+      .pipe(replaceStream(/from '(\.?\.\/[^']*)'/g, "from '$1.mjs'"))
+      .pipe(fs.createWriteStream(path.join(__dirname, "..", mjsFileName)))
+      .on("close", () => {
+        fs.unlinkSync(filePath);
+      });
+  }
+});

yarn.lock

@@ -3940,7 +3940,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"escape-string-regexp@npm:^1.0.5":
+"escape-string-regexp@npm:^1.0.3, escape-string-regexp@npm:^1.0.5":
   version: 1.0.5
   resolution: "escape-string-regexp@npm:1.0.5"
   checksum: f9484b8b4c8827d816e0fd905c25ed4b561376a9c220e1430403ea84619bf680c76a883a48cff8b8e091daf55d6a497e37479f9787b9f15f3c421b6054289744
@@ -4894,9 +4894,11 @@ __metadata:
     eslint: ^7.19.0
     eslint-config-prettier: ^7.2.0
     eslint-plugin-prettier: ^3.3.1
+    glob: ^7.1.6
     graphql: ^15.5.0
     jest: ^26.6.3
     prettier: ^2.2.1
+    replacestream: ^4.0.3
     rollup: ^2.38.5
     rollup-plugin-terser: ^7.0.2
     semantic-release: ^17.3.8
@@ -7938,7 +7940,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"object-assign@npm:^4.1.0":
+"object-assign@npm:^4.0.1, object-assign@npm:^4.1.0":
   version: 4.1.1
   resolution: "object-assign@npm:4.1.1"
   checksum: 66cf021898fc1b13ea573ea8635fbd5a76533f50cecbc2fcd5eee1e8029af41bcebe7023788b6d0e06cbe4401ecea075d972f78ec74467cdc571a0f1a4d1a081
@@ -9040,6 +9042,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"replacestream@npm:^4.0.3":
+  version: 4.0.3
+  resolution: "replacestream@npm:4.0.3"
+  dependencies:
+    escape-string-regexp: ^1.0.3
+    object-assign: ^4.0.1
+    readable-stream: ^2.0.2
+  checksum: 180c09f94ce428ef7cc8f97a8f0e3a68624b58a0e8814f458801ebb3543a65a6789ca5df599c142612d4df27b04056644df8761e0cd4294b9783950c45163e7b
+  languageName: node
+  linkType: hard
+
 "request-promise-core@npm:1.1.4":
   version: 1.1.4
   resolution: "request-promise-core@npm:1.1.4"