feat(useIterableCallbackReturn): add checkForEach option

.changeset/add-check-for-each-option.md

@@ -0,0 +1,11 @@
+---
+"@biomejs/biome": patch
+---
+
+Added the `checkForEach` option to the `useIterableCallbackReturn` rule.
+
+When `checkForEach` is `true`, the rule reports when `forEach` callbacks return a value. When `false` (the default), `forEach` callbacks are not checked.
+
+This aligns with ESLint's `array-callback-return` rule behavior where `forEach` checking is opt-in.
+
+**Breaking change:** Previously, `forEach` was always checked. Users who want the previous behavior should set `checkForEach: true` in their configuration.

crates/biome_js_analyze/src/lint/suspicious/use_iterable_callback_return.rs

@@ -45,7 +45,15 @@ declare_lint_rule! {
     /// - `toSorted`
     /// — `from` (when called on `Array`)
     ///
-    /// A return value is disallowed in the method `forEach`.
+    /// When `checkForEach` is enabled, a return value is disallowed in the method `forEach`.
+    ///
+    /// ## Options
+    ///
+    /// ### checkForEach
+    ///
+    /// If `true`, also check that callbacks to `forEach` do not return a value.
+    ///
+    /// Default: `false`
     ///
     /// ## Examples
     ///
@@ -57,12 +65,6 @@ declare_lint_rule! {
     /// });
     /// ```
     ///
-    /// ```js,expect_diagnostic
-    /// [].forEach(() => {
-    ///     return 1; // Should not return a value
-    /// });
-    /// ```
-    ///
     /// ### Valid
     ///
     /// ```js
@@ -72,14 +74,11 @@ declare_lint_rule! {
     /// ```
     ///
     /// ```js
+    /// // By default, forEach callbacks may return a value
     /// [].forEach(() => {
-    ///     // No return value, which is correct
+    ///     return 1;
     /// });
     /// ```
-    ///
-    /// ```js
-    /// [].forEach(() => void null); // Void return value, which doesn't trigger the rule
-    /// ```
     pub UseIterableCallbackReturn {
         version: "2.0.0",
         name: "useIterableCallbackReturn",
@@ -130,6 +129,11 @@ impl Rule for UseIterableCallbackReturn {
 
         let method_config = ITERABLE_METHOD_INFOS.get(member_name.text_trimmed())?;
 
+        // Skip forEach checks if checkForEach option is false
+        if member_name.text_trimmed() == "forEach" && !ctx.options().check_for_each() {
+            return None;
+        }
+
         let arg_position = argument_list
             .elements()
             .position(|arg| arg.node.is_ok() && arg.node.unwrap().syntax().eq(&cfg.node))?;

crates/biome_js_analyze/tests/specs/suspicious/useIterableCallbackReturn/invalid.js

@@ -1,32 +1,3 @@
-[].forEach((a) => {
-    return a.fn();
-});
-[].forEach(function(a) {
-    return a.fn();
-});
-[].forEach((a) => {
-    if (a) {
-        return a.fn();
-    }
-});
-[].forEach((a) => {
-    if (a) {
-        return;
-    }
-    return a.fn();
-});
-[].forEach((a) => {
-    if (a) {
-        return;
-    }
-    return a.fn();
-});
-[].forEach((a) => {
-    if (a) {
-        throw new Error();
-    }
-    return a.fn();
-});
 Array.from([], () => {});
 Array.from([], function() {});
 Array.from([], () => {