prefer-add-event-listener: Don't autofix non-function assignments (#2865)

sindresorhus · web-flow · commit 989ec61a3255 · 2026-02-09T15:54:57.000+07:00
diff --git a/rules/prefer-add-event-listener.js b/rules/prefer-add-event-listener.js
@@ -1,4 +1,4 @@
-import {isParenthesized} from './utils/index.js';
+import {isParenthesized, isNodeValueNotFunction} from './utils/index.js';
 import eventTypes from './shared/dom-events.js';
 import {isUndefined, isNullLiteral, isStaticRequire} from './ast/index.js';
 
@@ -138,6 +138,7 @@ const create = context => {
 			operator === '='
 			&& node.parent.type === 'ExpressionStatement'
 			&& node.parent.expression === node
+			&& !isNodeValueNotFunction(assignedExpression)
 		) {
 			fix = fixer => fixCode(fixer, context, node, memberExpression);
 		}
diff --git a/test/prefer-add-event-listener.js b/test/prefer-add-event-listener.js
@@ -165,6 +165,14 @@ test.snapshot({
 		'window.onunload ??= function() {};',
 		'window.onunload ||= function() {};',
 		'window.onunload += function() {};',
+		// Non-function values should not be autofixed
+		'foo.onclick = true',
+		'foo.onclick = \'bar\'',
+		'foo.onclick = `bar`',
+		'foo.onclick = {}',
+		'foo.onclick = []',
+		'foo.onclick = void 0',
+		'foo.onclick = new Handler()',
 	],
 });
 
diff --git a/test/snapshots/prefer-add-event-listener.js.md b/test/snapshots/prefer-add-event-listener.js.md
@@ -37,9 +37,6 @@ Generated by [AVA](https://avajs.dev).
     Message:␊
     > 1 | foo.onclick = 1␊
         |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
-    ␊
-    Output:␊
-      1 | foo.addEventListener('click', 1)␊
     `
 
 ## invalid(3): foo.bar.onclick = onClick
@@ -558,9 +555,6 @@ Generated by [AVA](https://avajs.dev).
     Message:␊
     > 1 | window.onload = window.onunload = function() {};␊
         |        ^^^^^^ Prefer \`addEventListener\` over \`onload\`.␊
-    ␊
-    Output:␊
-      1 | window.addEventListener('load', window.onunload = function() {});␊
     `
 
 > Error 2/2
@@ -618,3 +612,115 @@ Generated by [AVA](https://avajs.dev).
     > 1 | window.onunload += function() {};␊
         |        ^^^^^^^^ Prefer \`addEventListener\` over \`onunload\`.␊
     `
+
+## invalid(31): foo.onclick = true
+
+> Input
+
+    `␊
+      1 | foo.onclick = true␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | foo.onclick = true␊
+        |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
+    `
+
+## invalid(32): foo.onclick = 'bar'
+
+> Input
+
+    `␊
+      1 | foo.onclick = 'bar'␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | foo.onclick = 'bar'␊
+        |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
+    `
+
+## invalid(33): foo.onclick = `bar`
+
+> Input
+
+    `␊
+      1 | foo.onclick = \`bar\`␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | foo.onclick = \`bar\`␊
+        |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
+    `
+
+## invalid(34): foo.onclick = {}
+
+> Input
+
+    `␊
+      1 | foo.onclick = {}␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | foo.onclick = {}␊
+        |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
+    `
+
+## invalid(35): foo.onclick = []
+
+> Input
+
+    `␊
+      1 | foo.onclick = []␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | foo.onclick = []␊
+        |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
+    `
+
+## invalid(36): foo.onclick = void 0
+
+> Input
+
+    `␊
+      1 | foo.onclick = void 0␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | foo.onclick = void 0␊
+        |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
+    `
+
+## invalid(37): foo.onclick = new Handler()
+
+> Input
+
+    `␊
+      1 | foo.onclick = new Handler()␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+    > 1 | foo.onclick = new Handler()␊
+        |     ^^^^^^^ Prefer \`addEventListener\` over \`onclick\`.␊
+    `
diff --git a/test/snapshots/prefer-add-event-listener.js.snap b/test/snapshots/prefer-add-event-listener.js.snap
