feat(linter): add eslint/no-spaced-func

crates/oxc_linter/src/rules.rs

@@ -125,6 +125,7 @@ mod eslint {
     pub mod no_self_compare;
     pub mod no_setter_return;
     pub mod no_shadow_restricted_names;
+    pub mod no_spaced_func;
     pub mod no_sparse_arrays;
     pub mod no_template_curly_in_string;
     pub mod no_ternary;
@@ -564,6 +565,7 @@ oxc_macros::declare_all_lint_rules! {
     eslint::max_lines,
     eslint::max_params,
     eslint::new_cap,
+    eslint::no_spaced_func,
     eslint::no_useless_call,
     eslint::no_unneeded_ternary,
     eslint::no_extra_label,

crates/oxc_linter/src/rules/eslint/no_spaced_func.rs

@@ -0,0 +1,235 @@
+use memchr::memchr;
+use oxc_ast::AstKind;
+use oxc_ast::ast::Expression;
+use oxc_diagnostics::OxcDiagnostic;
+use oxc_macros::declare_oxc_lint;
+use oxc_span::{GetSpan, Span};
+
+use crate::{AstNode, context::LintContext, rule::Rule};
+
+fn no_spaced_func_diagnostic(span: Span) -> OxcDiagnostic {
+    OxcDiagnostic::warn(
+        "Spacing between function identifiers and their applications is disallowed.",
+    )
+    .with_label(span)
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct NoSpacedFunc;
+
+declare_oxc_lint!(
+    /// ### What it does
+    ///
+    /// This rule disallows spacing between function identifiers and their applications.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// While it’s possible to have whitespace between the name of a function and the parentheses
+    /// that execute it, such patterns tend to look more like errors.
+    ///
+    /// ### Examples
+    ///
+    /// Examples of **incorrect** code for this rule:
+    /// ```javascript
+    /// fn ()
+    /// ```
+    ///
+    /// ```javascript
+    /// fn
+    /// ()
+    /// ```
+    ///
+    /// ```javascript
+    /// f.b ()
+    /// ```
+    ///
+    /// Examples of **correct** code for this rule:
+    /// ```js
+    /// fn()
+    /// ```
+    ///
+    /// ```javascript
+    /// f.b()
+    /// ```
+    NoSpacedFunc,
+    eslint,
+    style,
+    fix
+);
+
+#[derive(PartialEq, Debug)]
+enum FuncSpace {
+    NotSpaced,
+    Spaced(Span),
+}
+
+/// Given an identifier reference will determine
+/// if there is spacing in the span from the end of the
+/// identifier name to the next `(` char.
+///
+/// For example `foo  ()` would return `FuncSpace::Spaced(span)`
+/// where span refers to the whitespace between `foo` and `()`.
+fn get_substring_to_lparens(ctx: &LintContext, search_span: Span) -> FuncSpace {
+    let src = ctx.source_range(search_span);
+
+    let Some(char_count) = memchr(b'(', src.as_bytes()) else {
+        return FuncSpace::NotSpaced;
+    };
+
+    let Ok(char_count_to_l_parens) = u32::try_from(char_count) else {
+        return FuncSpace::NotSpaced;
+    };
+
+    let l_parens_pos = search_span.start + char_count_to_l_parens;
+    let span_to_l_parens = Span::new(search_span.start, l_parens_pos);
+    let src_to_l_parens = ctx.source_range(span_to_l_parens);
+
+    if src_to_l_parens.is_empty() {
+        return FuncSpace::NotSpaced;
+    }
+
+    if src_to_l_parens.trim().is_empty() {
+        FuncSpace::Spaced(span_to_l_parens)
+    } else {
+        FuncSpace::NotSpaced
+    }
+}
+
+fn check_ident_to_application(ctx: &LintContext, span: Span) {
+    match get_substring_to_lparens(ctx, span) {
+        FuncSpace::NotSpaced => {}
+        FuncSpace::Spaced(span) => {
+            ctx.diagnostic_with_fix(no_spaced_func_diagnostic(span), |fixer| fixer.delete(&span));
+        }
+    }
+}
+
+impl Rule for NoSpacedFunc {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        if let AstKind::NewExpression(new_expr) = node.kind() {
+            // new Foo ()
+            let callee = new_expr.callee.without_parentheses();
+            let callee_end = callee.span().end;
+            let span = Span::new(callee_end, new_expr.span().end);
+
+            check_ident_to_application(ctx, span);
+        };
+
+        let AstKind::CallExpression(call_expr) = node.kind() else {
+            return;
+        };
+
+        let callee_end = call_expr.span().end;
+
+        match &call_expr.callee {
+            // f ()
+            Expression::Identifier(ident) => {
+                let span = Span::new(ident.span().end, callee_end);
+                check_ident_to_application(ctx, span);
+            }
+            Expression::ParenthesizedExpression(paren_exp) => {
+                if let Expression::Identifier(_ident) = &paren_exp.expression {
+                    let span = Span::new(paren_exp.span().end, callee_end);
+                    check_ident_to_application(ctx, span);
+                }
+            }
+            // f() () <-- second parens
+            Expression::CallExpression(c) => {
+                let span = Span::new(c.span().end, callee_end);
+                check_ident_to_application(ctx, span);
+            }
+            // f.a ()
+            Expression::StaticMemberExpression(exp) => {
+                let ident_name_span_end = exp.property.span().end;
+                let span = Span::new(ident_name_span_end, callee_end);
+
+                check_ident_to_application(ctx, span);
+            }
+            // function(){ } ()
+            Expression::FunctionExpression(func) => {
+                let span = Span::new(func.span().end, callee_end);
+                check_ident_to_application(ctx, span);
+            }
+            _ => {}
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "foo(1);",
+        "f();",
+        "f( );",
+        "f(a, b);",
+        "a.b",
+        "a. b",
+        "f.b();",
+        "f.b().c();",
+        "f.b(1).c( );",
+        "f()()",
+        "f()( )()",
+        "(function() {}())",
+        "var f = new Foo()",
+        "var f = new Foo",
+        "f( (0) )",
+        "( f )( 0 )",
+        "( (f) )( (0) )",
+        "( f()() )(0)",
+        "(function(){ if (foo) { bar(); } }());",
+        "f(0, (1))",
+        "describe/**/('foo', function () {});",
+        "new (foo())",
+    ];
+
+    let fail = vec![
+        "f ();",
+        "f (a, b);",
+        "f
+         	();",
+        "f.b ();",
+        "f.b().c ();",
+        "f.b().c().d ();",
+        "f() ()",
+        "f()() ()",
+        "(function() {} ())",
+        "var f = new Foo ()",
+        "f ( (0) )",
+        "f(0) (1)",
+        "(f) (0)",
+        "f ();
+			 t   ();",
+    ];
+
+    let fix = vec![
+        ("f ();", "f();", None),
+        ("f (a, b);", "f(a, b);", None),
+        (
+            "f
+            ();",
+            "f();",
+            None,
+        ),
+        ("f.b ();", "f.b();", None),
+        ("f.b().c ();", "f.b().c();", None),
+        ("f() ()", "f()()", None),
+        ("(function() {} ())", "(function() {}())", None),
+        ("var f = new Foo ()", "var f = new Foo()", None),
+        ("f ( (0) )", "f( (0) )", None),
+        ("f(0) (1)", "f(0)(1)", None),
+        ("(f) (0)", "(f)(0)", None),
+        (
+            "f ();
+             t   ();",
+            "f();
+             t();",
+            None,
+        ),
+    ];
+
+    Tester::new(NoSpacedFunc::NAME, NoSpacedFunc::PLUGIN, pass, fail)
+        .expect_fix(fix)
+        .test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/eslint_no_spaced_func.snap

@@ -0,0 +1,109 @@
+---
+source: crates/oxc_linter/src/tester.rs
+---
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:2]
+ 1 │ f ();
+   ·  ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:2]
+ 1 │ f (a, b);
+   ·  ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:2]
+ 1 │ ╭─▶ f
+ 2 │ ╰─▶             ();
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:4]
+ 1 │ f.b ();
+   ·    ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:8]
+ 1 │ f.b().c ();
+   ·        ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:12]
+ 1 │ f.b().c().d ();
+   ·            ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:4]
+ 1 │ f() ()
+   ·    ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:6]
+ 1 │ f()() ()
+   ·      ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:15]
+ 1 │ (function() {} ())
+   ·               ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:16]
+ 1 │ var f = new Foo ()
+   ·                ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:2]
+ 1 │ f ( (0) )
+   ·  ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:5]
+ 1 │ f(0) (1)
+   ·     ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:4]
+ 1 │ (f) (0)
+   ·    ─
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:1:2]
+ 1 │ f ();
+   ·  ─
+ 2 │              t   ();
+   ╰────
+  help: Delete this code.
+
+  ⚠ eslint(no-spaced-func): Spacing between function identifiers and their applications is disallowed.
+   ╭─[no_spaced_func.tsx:2:6]
+ 1 │ f ();
+ 2 │              t   ();
+   ·               ───
+   ╰────
+  help: Delete this code.