feat(linter): unicorn/no-anonymous-default-export (#3220)

Refer to
[eslint-plugin-unicorn/no-anonymous-default-export](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v52.0.0/docs/rules/no-anonymous-default-export.md)

link: #684

---------

Co-authored-by: Boshen <boshenc@gmail.com>

crates/oxc_linter/src/rules.rs

@@ -227,6 +227,7 @@ mod unicorn {
     pub mod filename_case;
     pub mod new_for_builtins;
     pub mod no_abusive_eslint_disable;
+    pub mod no_anonymous_default_export;
     pub mod no_array_for_each;
     pub mod no_array_reduce;
     pub mod no_await_expression_member;
@@ -545,6 +546,7 @@ oxc_macros::declare_all_lint_rules! {
     unicorn::filename_case,
     unicorn::new_for_builtins,
     unicorn::no_abusive_eslint_disable,
+    unicorn::no_anonymous_default_export,
     unicorn::no_array_for_each,
     unicorn::no_array_reduce,
     unicorn::no_await_expression_member,

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

@@ -0,0 +1,166 @@
+use oxc_ast::{
+    ast::{AssignmentExpression, AssignmentTarget, ExportDefaultDeclarationKind, Expression},
+    AstKind,
+};
+use oxc_diagnostics::OxcDiagnostic;
+use oxc_macros::declare_oxc_lint;
+use oxc_span::Span;
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+fn no_anonymous_default_export_diagnostic(span0: Span, x1: &str) -> OxcDiagnostic {
+    OxcDiagnostic::warning("eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export")
+        .with_help(format!("The {x1} should be named."))
+        .with_labels([span0.into()])
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct NoAnonymousDefaultExport;
+
+declare_oxc_lint!(
+    /// ### What it does
+    /// Disallow anonymous functions and classes as the default export
+    ///
+    /// ### Why is this bad?
+    /// Naming default exports improves codebase searchability by ensuring consistent identifier use for a module's default export, both where it's declared and where it's imported.
+    ///
+    /// ### Example
+    /// ```javascript
+    /// // Bad
+    /// export default class {}
+    /// export default function () {}
+    /// export default () => {};
+    /// module.exports = class {};
+    /// module.exports = function () {};
+    /// module.exports = () => {};
+    ///
+    /// // Good
+    /// export default class Foo {}
+    /// export default function foo () {}
+    ///
+    /// const foo = () => {};
+    /// export default foo;
+    ///
+    /// module.exports = class Foo {};
+    /// module.exports = function foo () {};
+    ///
+    /// const foo = () => {};
+    /// module.exports = foo;
+    /// ```
+    NoAnonymousDefaultExport,
+    restriction,
+);
+
+impl Rule for NoAnonymousDefaultExport {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        let problem_node = match node.kind() {
+            // ESM: export default
+            AstKind::ExportDefaultDeclaration(export_decl) => match &export_decl.declaration {
+                ExportDefaultDeclarationKind::ClassDeclaration(class_decl) => class_decl
+                    .id
+                    .as_ref()
+                    .map_or(Some((export_decl.span, ErrorNodeKind::Class)), |_| None),
+                ExportDefaultDeclarationKind::FunctionDeclaration(function_decl) => function_decl
+                    .id
+                    .as_ref()
+                    .map_or(Some((export_decl.span, ErrorNodeKind::Function)), |_| None),
+                ExportDefaultDeclarationKind::ArrowFunctionExpression(_) => {
+                    Some((export_decl.span, ErrorNodeKind::Function))
+                }
+                ExportDefaultDeclarationKind::ParenthesizedExpression(expr) => {
+                    let expr = expr.expression.get_inner_expression();
+                    match expr {
+                        Expression::ClassExpression(class_expr) => class_expr
+                            .id
+                            .as_ref()
+                            .map_or(Some((class_expr.span, ErrorNodeKind::Class)), |_| None),
+                        Expression::FunctionExpression(func_expr) => func_expr
+                            .id
+                            .as_ref()
+                            .map_or(Some((func_expr.span, ErrorNodeKind::Function)), |_| None),
+                        _ => None,
+                    }
+                }
+                _ => None,
+            },
+            // CommonJS: module.exports
+            AstKind::AssignmentExpression(expr) if is_common_js_export(expr) => match &expr.right {
+                Expression::ClassExpression(class_expr) => {
+                    class_expr.id.as_ref().map_or(Some((expr.span, ErrorNodeKind::Class)), |_| None)
+                }
+                Expression::FunctionExpression(function_expr) => function_expr
+                    .id
+                    .as_ref()
+                    .map_or(Some((expr.span, ErrorNodeKind::Function)), |_| None),
+                Expression::ArrowFunctionExpression(_) => {
+                    Some((expr.span, ErrorNodeKind::Function))
+                }
+                _ => None,
+            },
+            _ => None,
+        };
+
+        if let Some((span, error_kind)) = problem_node {
+            ctx.diagnostic(no_anonymous_default_export_diagnostic(span, error_kind.as_str()));
+        };
+    }
+}
+
+fn is_common_js_export(expr: &AssignmentExpression) -> bool {
+    if let AssignmentTarget::StaticMemberExpression(member_expr) = &expr.left {
+        if let Expression::Identifier(object_ident) = &member_expr.object {
+            if object_ident.name != "module" {
+                return false;
+            }
+        }
+
+        if member_expr.property.name != "exports" {
+            return false;
+        }
+    }
+
+    true
+}
+
+enum ErrorNodeKind {
+    Function,
+    Class,
+}
+
+impl ErrorNodeKind {
+    fn as_str(&self) -> &str {
+        match self {
+            Self::Function => "function",
+            Self::Class => "class",
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        r"export default class Foo {}",
+        r"export default function foo () {}",
+        r"const foo = () => {}; export default foo;",
+        r"module.exports = class Foo {};",
+        r"module.exports = function foo () {};",
+        r"const foo = () => {}; module.exports = foo;",
+        // TODO: need handle this situation?
+        // r"module['exports'] = function foo () {};",
+    ];
+
+    let fail = vec![
+        r"export default class {}",
+        r"export default function () {}",
+        r"export default () => {};",
+        r"module.exports = class {}",
+        r"module.exports = function () {}",
+        r"module.exports = () => {}",
+        "export default (async function * () {})",
+        "export default (class extends class {} {})",
+    ];
+
+    Tester::new(NoAnonymousDefaultExport::NAME, pass, fail).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/no_anonymous_default_export.snap

@@ -0,0 +1,59 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: no_anonymous_default_export
+---
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:1]
+ 1 │ export default class {}
+   · ───────────────────────
+   ╰────
+  help: The class should be named.
+
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:1]
+ 1 │ export default function () {}
+   · ─────────────────────────────
+   ╰────
+  help: The function should be named.
+
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:1]
+ 1 │ export default () => {};
+   · ────────────────────────
+   ╰────
+  help: The function should be named.
+
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:1]
+ 1 │ module.exports = class {}
+   · ─────────────────────────
+   ╰────
+  help: The class should be named.
+
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:1]
+ 1 │ module.exports = function () {}
+   · ───────────────────────────────
+   ╰────
+  help: The function should be named.
+
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:1]
+ 1 │ module.exports = () => {}
+   · ─────────────────────────
+   ╰────
+  help: The function should be named.
+
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:17]
+ 1 │ export default (async function * () {})
+   ·                 ──────────────────────
+   ╰────
+  help: The function should be named.
+
+  ⚠ eslint-plugin-unicorn(no-anonymous-default-export): Disallow anonymous functions and classes as the default export
+   ╭─[no_anonymous_default_export.tsx:1:17]
+ 1 │ export default (class extends class {} {})
+   ·                 ─────────────────────────
+   ╰────
+  help: The class should be named.