refactor: improve fixer

oxc-project · Oct 19, 2024 · 9871a55 · 9871a55
1 parent 4dfefe1
commit 9871a55
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Showing 2 changed files with 28 additions and 14 deletions.
diff --git a/crates/oxc_linter/src/rules/unicorn/no_useless_spread/mod.rs b/crates/oxc_linter/src/rules/unicorn/no_useless_spread/mod.rs
@@ -389,24 +389,30 @@ fn check_useless_clone<'a>(
         return;
     }
 
-    // unsafe fixer of `[...new Array(1)]`
-    if let Expression::NewExpression(new_expr) = target {
-        let is_array_constructor = new_expr
-            .callee
-            .without_parentheses()
-            .get_identifier_reference()
-            .is_some_and(|id| id.name == "Array");
-
-        if is_array_constructor && new_expr.arguments.len() == 1 {
-            return;
-        }
-    }
-
     let hint = target.const_eval();
     let hint_matches_expr = if is_array { hint.is_array() } else { hint.is_object() };
     if hint_matches_expr {
         let name = diagnostic_name(ctx, target);
 
+        // `[...new Array(1)]` -> `new Array(1).fill()`
+        if let Expression::NewExpression(new_expr) = target {
+            let is_array_constructor = new_expr
+                .callee
+                .without_parentheses()
+                .get_identifier_reference()
+                .is_some_and(|id| id.name == "Array");
+
+            if is_array_constructor && new_expr.arguments.len() == 1 {
+                ctx.diagnostic_with_fix(clone(span, is_array, name), |fixer| {
+                    fixer.replace(
+                        array_or_obj_span,
+                        format!("{}.fill()", fixer.source_range(spread_elem.argument.span())),
+                    )
+                });
+                return;
+            }
+        }
+
         ctx.diagnostic_with_fix(clone(span, is_array, name), |fixer| {
             fix_by_removing_array_spread(fixer, &array_or_obj_span, spread_elem)
         });
@@ -588,7 +594,6 @@ fn test() {
         "[...arr.reduce((set, b) => set.add(b), new Set(iter))]",
         // NOTE: we may want to consider this a violation in the future
         "[...(foo ? new Set() : [])]",
-        "[...new Array(3)]",
     ];
 
     let fail = vec![
@@ -678,6 +683,7 @@ fn test() {
         r"[...foo.toSpliced(0, 1)]",
         r"[...foo.with(0, bar)]",
         r#"[...foo.split("|")]"#,
+        r"[...new Array(3)]",
         r"[...Object.keys(foo)]",
         r"[...Object.values(foo)]",
         r"[...Array.from(foo)]",
@@ -736,6 +742,7 @@ fn test() {
         // useless clones - simple arrays
         ("[...foo.map(x => !!x)]", "foo.map(x => !!x)"),
         ("[...new Array()]", "new Array()"),
+        ("[...new Array(3)]", "new Array(3).fill()"),
         ("[...new Array(1, 2, 3)]", "new Array(1, 2, 3)"),
         // useless clones - complex
         (r"[...await Promise.all(foo)]", r"await Promise.all(foo)"),

diff --git a/crates/oxc_linter/src/snapshots/no_useless_spread.snap b/crates/oxc_linter/src/snapshots/no_useless_spread.snap
@@ -637,6 +637,13 @@ source: crates/oxc_linter/src/tester.rs
    ╰────
   help: `foo.split` returns a new array. Spreading it into an array expression to create a new array is redundant.
 
+  ⚠ eslint-plugin-unicorn(no-useless-spread): Using a spread operator here creates a new array unnecessarily.
+   ╭─[no_useless_spread.tsx:1:2]
+ 1 │ [...new Array(3)]
+   ·  ───
+   ╰────
+  help: `new Array(3)` returns a new array. Spreading it into an array expression to create a new array is redundant.
+
   ⚠ eslint-plugin-unicorn(no-useless-spread): Using a spread operator here creates a new array unnecessarily.
    ╭─[no_useless_spread.tsx:1:2]
  1 │ [...Object.keys(foo)]