feat(linter): typescript-eslint/prefer-enum-initializers (#3097)

crates/oxc_linter/src/rules.rs

@@ -138,6 +138,7 @@ mod typescript {
     pub mod no_unsafe_declaration_merging;
     pub mod no_var_requires;
     pub mod prefer_as_const;
+    pub mod prefer_enum_initializers;
     pub mod prefer_for_of;
     pub mod prefer_function_type;
     pub mod prefer_ts_expect_error;
@@ -471,6 +472,7 @@ oxc_macros::declare_all_lint_rules! {
     typescript::array_type,
     typescript::ban_ts_comment,
     typescript::ban_tslint_comment,
+    typescript::prefer_enum_initializers,
     typescript::ban_types,
     typescript::consistent_type_definitions,
     typescript::no_duplicate_enum_values,

crates/oxc_linter/src/rules/typescript/prefer_enum_initializers.rs

@@ -0,0 +1,110 @@
+use oxc_ast::{ast::TSEnumMemberName, AstKind};
+use oxc_diagnostics::{
+    miette::{self, Diagnostic},
+    thiserror::Error,
+};
+use oxc_macros::declare_oxc_lint;
+use oxc_span::{CompactStr, Span};
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("typescript-eslint(prefer-enum-initializers):The value of the member {0:?} should be explicitly defined.")]
+#[diagnostic(severity(warning), help("Can be fixed to {0:?} = {1:?}."))]
+struct PreferEnumInitializersDiagnostic(CompactStr, usize, #[label] pub Span);
+
+#[derive(Debug, Default, Clone)]
+pub struct PreferEnumInitializers;
+
+declare_oxc_lint!(
+    /// ### What it does
+    /// Require each enum member value to be explicitly initialized.
+    ///
+    /// ### Why is this bad?
+    /// In projects where the value of `enum` members are important, allowing implicit values for enums can cause bugs if enums are modified over time.
+    ///
+    /// ### Example
+    /// ```typescript
+    /// // wrong, the value of `Close` is not constant
+    /// enum Status {
+    ///  Open = 1,
+    ///  Close,
+    /// }
+    /// ```
+    PreferEnumInitializers,
+    pedantic
+);
+
+impl Rule for PreferEnumInitializers {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        let AstKind::TSEnumDeclaration(decl) = node.kind() else { return };
+
+        for (index, member) in decl.members.iter().enumerate() {
+            if member.initializer.is_none() {
+                if let TSEnumMemberName::Identifier(i) = &member.id {
+                    ctx.diagnostic(PreferEnumInitializersDiagnostic(
+                        i.name.to_compact_str(),
+                        index + 1,
+                        member.span,
+                    ));
+                }
+            }
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "
+			enum Direction {}
+			    ",
+        "
+			enum Direction {
+			  Up = 1,
+			}
+			    ",
+        "
+			enum Direction {
+			  Up = 1,
+			  Down = 2,
+			}
+			    ",
+        "
+			enum Direction {
+			  Up = 'Up',
+			  Down = 'Down',
+			}
+			    ",
+    ];
+
+    let fail = vec![
+        "
+			enum Direction {
+			  Up,
+			}
+			      ",
+        "
+			enum Direction {
+			  Up,
+			  Down,
+			}
+			      ",
+        "
+			enum Direction {
+			  Up = 'Up',
+			  Down,
+			}
+			      ",
+        "
+			enum Direction {
+			  Up,
+			  Down = 'Down',
+			}
+			      ",
+    ];
+
+    Tester::new(PreferEnumInitializers::NAME, pass, fail).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/prefer_enum_initializers.snap

@@ -0,0 +1,48 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: prefer_enum_initializers
+---
+  ⚠ typescript-eslint(prefer-enum-initializers):The value of the member "Up" should be explicitly defined.
+   ╭─[prefer_enum_initializers.tsx:3:6]
+ 2 │             enum Direction {
+ 3 │               Up,
+   ·               ──
+ 4 │             }
+   ╰────
+  help: Can be fixed to "Up" = 1.
+
+  ⚠ typescript-eslint(prefer-enum-initializers):The value of the member "Up" should be explicitly defined.
+   ╭─[prefer_enum_initializers.tsx:3:6]
+ 2 │             enum Direction {
+ 3 │               Up,
+   ·               ──
+ 4 │               Down,
+   ╰────
+  help: Can be fixed to "Up" = 1.
+
+  ⚠ typescript-eslint(prefer-enum-initializers):The value of the member "Down" should be explicitly defined.
+   ╭─[prefer_enum_initializers.tsx:4:6]
+ 3 │               Up,
+ 4 │               Down,
+   ·               ────
+ 5 │             }
+   ╰────
+  help: Can be fixed to "Down" = 2.
+
+  ⚠ typescript-eslint(prefer-enum-initializers):The value of the member "Down" should be explicitly defined.
+   ╭─[prefer_enum_initializers.tsx:4:6]
+ 3 │               Up = 'Up',
+ 4 │               Down,
+   ·               ────
+ 5 │             }
+   ╰────
+  help: Can be fixed to "Down" = 2.
+
+  ⚠ typescript-eslint(prefer-enum-initializers):The value of the member "Up" should be explicitly defined.
+   ╭─[prefer_enum_initializers.tsx:3:6]
+ 2 │             enum Direction {
+ 3 │               Up,
+   ·               ──
+ 4 │               Down = 'Down',
+   ╰────
+  help: Can be fixed to "Up" = 1.