add linter

.github/workflows/pull-request.yml

@@ -16,6 +16,16 @@ jobs:
         node-version: 20.6.1
     - run: npm run limits
 
+  linter:
+    name: Code Linter
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v1
+      with:
+        node-version: 20.6.1
+    - run: npm run lint
+
   package-report:
     runs-on: ubuntu-latest
     steps:

.npmignore

@@ -2,3 +2,5 @@ test/
 test.sh
 .github/
 limitation.js
+eslint*
+*.sw?

eslint.config.mjs

@@ -0,0 +1,11 @@
+import globals from "globals";
+import pluginJs from "@eslint/js";
+
+export default [
+  {files: ["**/*.js"], languageOptions: {sourceType: "commonjs"}},
+  {languageOptions: { globals: globals.node }},
+  pluginJs.configs.recommended,
+  {rules: {
+    "semi": "error",
+  }}
+];

package.json

@@ -5,6 +5,7 @@
   "main": "dc-polyfill.js",
   "scripts": {
     "test": "./test.sh",
+    "lint": "eslint .",
     "limits": "./limitation.js"
   },
   "keywords": [
@@ -25,6 +26,9 @@
     "url": "https://github.com/DataDog/dc-polyfill/issues"
   },
   "devDependencies": {
+    "@eslint/js": "^9.2.0",
+    "eslint": "^9.2.0",
+    "globals": "^15.1.0",
     "tape": "^5.6.6"
   },
   "limits": {

patch-channel-unsubscribe-return.js

@@ -7,7 +7,6 @@ module.exports = function (unpatched) {
   const channels = new WeakSet();
 
   const dc_channel = unpatched.channel;
-  const dc_Channel = unpatched.Channel;
 
   const dc = { ...unpatched };
 

reimplementation.js

@@ -11,7 +11,6 @@ const {
  * It has been extended to support a global, cross-package-instance registry of channels
  */
 
-const util = require('util');
 const { ERR_INVALID_ARG_TYPE } = require('./errors.js');
 
 const channels = require('./acquire-channel-registry.js');
@@ -32,7 +31,7 @@ class ActiveChannel {
 
     // When there are no more active subscribers, restore to fast prototype.
     if (!this._subscribers.length) {
-      // eslint-disable-next-line no-use-before-define
+       
       ObjectSetPrototypeOf(this, Channel.prototype);
     }
 

test/common.js

@@ -10,7 +10,7 @@ function getCallSite(top) {
   const err = new Error();
   Error.captureStackTrace(err, top);
   // With the V8 Error API, the stack is not formatted until it is accessed
-  err.stack; // eslint-disable-line no-unused-expressions
+  err.stack;  
   Error.prepareStackTrace = originalStackFormatter;
   return err.stack;
 }
@@ -80,7 +80,7 @@ function _mustCallInner(fn, criteria = 1, field) {
 
   mustCallChecks.push(context);
 
-  const _return = function() { // eslint-disable-line func-style
+  const _return = function() {  
     context.actual++;
     return fn.apply(this, arguments);
   };

test/shared-channel-registry.spec.js

@@ -1,6 +1,5 @@
 'use strict';
 
-const path = require('path');
 const test = require('tape');
 const common = require('./common.js');
 const checks = require('../checks.js');
@@ -33,7 +32,7 @@ test('shared-channel-registry', (t) => {
 
   dc_v1.subscribe('foo', common.mustCall(function(msg) {
     t.equal(msg, 'bar');
-  }))
+  }));
 
   dc_v2.channel('foo').publish('bar');
 });

test/test-diagnostics-channel-has-subscribers.spec.js

@@ -1,6 +1,5 @@
 'use strict';
 
-const assert = require('assert');
 const test = require('tape');
 
 const { channel, hasSubscribers } = require('../dc-polyfill.js');
@@ -14,7 +13,7 @@ test('test-diagnostics-channel-has-subscribers', t => {
     // TypeError: WeakRefPrototypeGet is not a function
     t.comment('SKIPPING TEST DUE TO A BUG IN THIS VERSION OF NODE.JS');
     t.end();
-    return
+    return;
   }
 
   const dc = channel('test-diagnostics-channel-has-subscribers');

test/test-diagnostics-channel-memory-leak.spec.js

@@ -3,7 +3,6 @@
 // This test ensures that diagnostic channel references aren't leaked.
 
 const test = require('tape');
-const common = require('./common.js');
 const { subscribe, unsubscribe } = require('../dc-polyfill.js');
 
 const v8 = require('v8');

test/test-diagnostics-channel-safe-subscriber-errors.spec.js

@@ -18,7 +18,7 @@ test('test-diagnostics-channel-http', (t) => {
     t.strictEqual(err, error);
   }));
 
-  channel.subscribe(common.mustCall((message, name) => {
+  channel.subscribe(common.mustCall(() => {
     throw error;
   }));
 

test/test-diagnostics-channel-tracing-channel-async.spec.js

@@ -3,7 +3,7 @@
 const test = require('tape');
 const common = require('./common.js');
 const dc = require('../dc-polyfill.js');
-const { MAJOR, MINOR } = require('../checks.js');
+const { MAJOR } = require('../checks.js');
 
 test('test-diagnostics-channel-tracing-channel-async', (t) => {
   t.plan(23);

test/test-diagnostics-channel-worker-threads.spec.js

@@ -3,7 +3,7 @@ const test = require('tape');
 const common = require('./common.js');
 const dc = require('../dc-polyfill.js');
 const { Worker } = require('worker_threads');
-const { MAJOR, MINOR } = require('../checks.js');
+const { MAJOR } = require('../checks.js');
 
 // This test depends on features only available in certain versions of Node.js
 if (MAJOR < 19) return;