feat(linter) eslint plugin unicorn: prefer event target (#1465)

crates/oxc_linter/src/rules.rs

@@ -180,6 +180,7 @@ mod unicorn {
     pub mod prefer_date_now;
     pub mod prefer_dom_node_append;
     pub mod prefer_dom_node_dataset;
+    pub mod prefer_event_target;
     pub mod prefer_logical_operator_over_ternary;
     pub mod prefer_optional_catch_binding;
     pub mod prefer_query_selector;
@@ -343,6 +344,7 @@ oxc_macros::declare_all_lint_rules! {
     unicorn::prefer_date_now,
     unicorn::prefer_dom_node_append,
     unicorn::prefer_dom_node_dataset,
+    unicorn::prefer_event_target,
     unicorn::prefer_logical_operator_over_ternary,
     unicorn::prefer_optional_catch_binding,
     unicorn::prefer_query_selector,

crates/oxc_linter/src/rules/unicorn/prefer_event_target.rs

@@ -0,0 +1,111 @@
+use oxc_ast::{ast::Expression, AstKind};
+use oxc_diagnostics::{
+    miette::{self, Diagnostic},
+    thiserror::Error,
+};
+use oxc_macros::declare_oxc_lint;
+use oxc_span::Span;
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`")]
+#[diagnostic(severity(warning), help("Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers."))]
+struct PreferEventTargetDiagnostic(#[label] pub Span);
+
+#[derive(Debug, Default, Clone)]
+pub struct PreferEventTarget;
+
+declare_oxc_lint!(
+    /// ### What it does
+    ///
+    /// Prefers `EventTarget` over `EventEmitter`.
+    ///
+    /// This rule reduces the bundle size and makes your code more cross-platform friendly.
+    ///
+    /// See the [differences](https://nodejs.org/api/events.html#eventtarget-and-event-api) between `EventEmitter` and `EventTarget`.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// While [`EventEmitter`](https://nodejs.org/api/events.html#class-eventemitter) is only available in Node.js, [`EventTarget`](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget) is also available in _Deno_ and browsers.
+    ///
+    /// ### Example
+    /// ```javascript
+    /// // Bad
+    /// class Foo extends EventEmitter {}
+    ///
+    /// // Good
+    /// class Foo extends OtherClass {}
+    /// ```
+    PreferEventTarget,
+    pedantic
+);
+
+impl Rule for PreferEventTarget {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        let AstKind::IdentifierReference(ident) = node.kind() else { return };
+
+        if ident.name.as_str() != "EventEmitter" {
+            return;
+        }
+
+        let Some(parent) = ctx.nodes().parent_node(node.id()) else {
+            return;
+        };
+
+        match parent.kind() {
+            AstKind::ClassHeritage(_) => {}
+            AstKind::NewExpression(new_expr) => {
+                let Expression::Identifier(callee_ident) = &new_expr.callee else {
+                    return;
+                };
+
+                if ident as *const _ != callee_ident.0 as *const _ {
+                    return;
+                }
+            }
+            _ => return,
+        };
+
+        ctx.diagnostic(PreferEventTargetDiagnostic(ident.span));
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        r"class Foo {}",
+        r"class Foo extends OtherClass {}",
+        r"class Foo extends EventTarget {}",
+        r"const Foo = class extends EventTarget {}",
+        r"const Foo = class extends foo.EventTarget {}",
+        r"const Foo = class extends foo.bar.EventTarget {}",
+        r"class Foo extends foo.EventEmitter {}",
+        r"class Foo extends foo.bar.EventEmitter {}",
+        r"class EventEmitter extends Foo {}",
+        r"const Foo = class EventEmitter extends Foo {}",
+        r"new Foo(EventEmitter)",
+        r"new foo.EventEmitter()",
+        r"EventTarget()",
+        r"new EventTarget",
+        r"const target = new EventTarget;",
+        r"const target = EventTarget()",
+        r"const target = new Foo(EventEmitter);",
+        r"EventEmitter()",
+        r"const emitter = EventEmitter()",
+    ];
+
+    let fail = vec![
+        r"class Foo extends EventEmitter {}",
+        r"class Foo extends EventEmitter { someMethod() {} }",
+        r"const Foo = class extends EventEmitter {}",
+        r"new EventEmitter",
+        r"const emitter = new EventEmitter;",
+        r"for (const {EventEmitter} of []) {new EventEmitter}",
+        r"for (const EventEmitter of []) {new EventEmitter}",
+    ];
+
+    Tester::new_without_config(PreferEventTarget::NAME, pass, fail).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/prefer_event_target.snap

@@ -0,0 +1,54 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: prefer_event_target
+---
+  ⚠ eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`
+   ╭─[prefer_event_target.tsx:1:1]
+ 1 │ class Foo extends EventEmitter {}
+   ·                   ────────────
+   ╰────
+  help: Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers.
+
+  ⚠ eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`
+   ╭─[prefer_event_target.tsx:1:1]
+ 1 │ class Foo extends EventEmitter { someMethod() {} }
+   ·                   ────────────
+   ╰────
+  help: Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers.
+
+  ⚠ eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`
+   ╭─[prefer_event_target.tsx:1:1]
+ 1 │ const Foo = class extends EventEmitter {}
+   ·                           ────────────
+   ╰────
+  help: Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers.
+
+  ⚠ eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`
+   ╭─[prefer_event_target.tsx:1:1]
+ 1 │ new EventEmitter
+   ·     ────────────
+   ╰────
+  help: Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers.
+
+  ⚠ eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`
+   ╭─[prefer_event_target.tsx:1:1]
+ 1 │ const emitter = new EventEmitter;
+   ·                     ────────────
+   ╰────
+  help: Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers.
+
+  ⚠ eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`
+   ╭─[prefer_event_target.tsx:1:1]
+ 1 │ for (const {EventEmitter} of []) {new EventEmitter}
+   ·                                       ────────────
+   ╰────
+  help: Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers.
+
+  ⚠ eslint-plugin-unicorn(prefer-event-target): Prefer `EventTarget` over `EventEmitter`
+   ╭─[prefer_event_target.tsx:1:1]
+ 1 │ for (const EventEmitter of []) {new EventEmitter}
+   ·                                     ────────────
+   ╰────
+  help: Change `EventEmitter` to `EventTarget`. EventEmitters are only available in Node.js, while EventTargets are also available in browsers.
+
+