feat(linter): default_param_last

crates/oxc_linter/src/rules.rs

@@ -40,6 +40,7 @@ mod eslint {
     pub mod array_callback_return;
     pub mod constructor_super;
     pub mod default_case_last;
+    pub mod default_param_last;
     pub mod eqeqeq;
     pub mod for_direction;
     pub mod getter_return;
@@ -358,6 +359,7 @@ oxc_macros::declare_all_lint_rules! {
     eslint::array_callback_return,
     eslint::constructor_super,
     eslint::default_case_last,
+    eslint::default_param_last,
     eslint::eqeqeq,
     eslint::for_direction,
     eslint::getter_return,

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

@@ -0,0 +1,118 @@
+use oxc_ast::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(default-param-last): Default parameters should be last")]
+#[diagnostic(severity(warning), help("Enforce default parameters to be last."))]
+struct DefaultParamLastDiagnostic(#[label] pub Span);
+
+#[derive(Debug, Default, Clone)]
+pub struct DefaultParamLast;
+
+declare_oxc_lint!(
+    /// ### What it does
+    /// Enforce default parameters to be last
+    ///
+    /// ### Why is this bad?
+    /// Putting default parameter at last allows function calls to omit optional tail arguments.
+    ///
+    /// ### Example
+    /// ```javascript
+    /// // Correct: optional argument can be omitted
+    /// function createUser(id, isAdmin = false) {}
+    /// createUser("tabby")
+    ///
+    /// // Incorrect: optional argument can **not** be omitted
+    /// function createUser(isAdmin = false, id) {}
+    /// createUser(undefined, "tabby")
+    /// ```
+    DefaultParamLast,
+    style
+);
+
+impl Rule for DefaultParamLast {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        match node.kind() {
+            AstKind::Function(function) => {
+                if !function.is_declaration() & !function.is_expression() {
+                    return;
+                }
+                let mut has_seen_plain_param = false;
+                for i in (0..function.params.items.len()).rev() {
+                    let param = &function.params.items[i];
+                    if !param.pattern.kind.is_assignment_pattern() {
+                        has_seen_plain_param = true;
+                        continue;
+                    }
+                    if has_seen_plain_param & param.pattern.kind.is_assignment_pattern() {
+                        ctx.diagnostic(DefaultParamLastDiagnostic(Span::new(
+                            param.span.start,
+                            param.span.end,
+                        )));
+                    }
+                }
+            }
+            AstKind::ArrowFunctionExpression(function) => {
+                let mut has_seen_plain_param = false;
+                for i in (0..function.params.items.len()).rev() {
+                    let param = &function.params.items[i];
+                    if !param.pattern.kind.is_assignment_pattern() {
+                        has_seen_plain_param = true;
+                        continue;
+                    }
+                    if has_seen_plain_param & param.pattern.kind.is_assignment_pattern() {
+                        ctx.diagnostic(DefaultParamLastDiagnostic(Span::new(
+                            param.span.start,
+                            param.span.end,
+                        )));
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "function f() {}",
+        "function f(a) {}",
+        "function f(a = 5) {}",
+        "function f(a, b) {}",
+        "function f(a, b = 5) {}",
+        "function f(a, b = 5, c = 5) {}",
+        "function f(a, b = 5, ...c) {}",
+        "const f = () => {}",
+        "const f = (a) => {}",
+        "const f = (a = 5) => {}",
+        "const f = function f() {}",
+        "const f = function f(a) {}",
+        "const f = function f(a = 5) {}",
+    ];
+
+    let fail = vec![
+        "function f(a = 5, b) {}",
+        "function f(a = 5, b = 6, c) {}",
+        "function f (a = 5, b, c = 6, d) {}",
+        "function f(a = 5, b, c = 5) {}",
+        "const f = (a = 5, b, ...c) => {}",
+        "const f = function f (a, b = 5, c) {}",
+        "const f = (a = 5, { b }) => {}",
+        "const f = ({ a } = {}, b) => {}",
+        "const f = ({ a, b } = { a: 1, b: 2 }, c) => {}",
+        "const f = ([a] = [], b) => {}",
+        "const f = ([a, b] = [1, 2], c) => {}",
+    ];
+
+    Tester::new(DefaultParamLast::NAME, pass, fail).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/default_param_last.snap

@@ -0,0 +1,94 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: default_param_last
+---
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ function f(a = 5, b) {}
+   ·            ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:19]
+ 1 │ function f(a = 5, b = 6, c) {}
+   ·                   ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ function f(a = 5, b = 6, c) {}
+   ·            ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:23]
+ 1 │ function f (a = 5, b, c = 6, d) {}
+   ·                       ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:13]
+ 1 │ function f (a = 5, b, c = 6, d) {}
+   ·             ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ function f(a = 5, b, c = 5) {}
+   ·            ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ const f = (a = 5, b, ...c) => {}
+   ·            ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:26]
+ 1 │ const f = function f (a, b = 5, c) {}
+   ·                          ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ const f = (a = 5, { b }) => {}
+   ·            ─────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ const f = ({ a } = {}, b) => {}
+   ·            ──────────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ const f = ({ a, b } = { a: 1, b: 2 }, c) => {}
+   ·            ─────────────────────────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ const f = ([a] = [], b) => {}
+   ·            ────────
+   ╰────
+  help: Enforce default parameters to be last.
+
+  ⚠ eslint(default-param-last): Default parameters should be last
+   ╭─[default_param_last.tsx:1:12]
+ 1 │ const f = ([a, b] = [1, 2], c) => {}
+   ·            ───────────────
+   ╰────
+  help: Enforce default parameters to be last.