fix(linter/prefer-array-flat-map): error for .flat(1.0)

Author: overlookmotel

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

@@ -68,11 +68,10 @@ impl Rule for PreferArrayFlatMap {
         }
 
         if let Some(first_arg) = flat_call_expr.arguments.first() {
-            if let Argument::NumericLiteral(number_lit) = first_arg {
-                if number_lit.raw.as_ref().unwrap() != "1" {
-                    return;
-                }
-            } else {
+            // Strict comparison of `f64`s with `==` is appropriate here, because `lit.value` is derived
+            // from a literal value in source, not from a calculation which might introduce imprecision
+            #[expect(clippy::float_cmp)]
+            if !matches!(first_arg, Argument::NumericLiteral(lit) if lit.value == 1.0) {
                 return;
             }
         }
@@ -107,6 +106,9 @@ fn test() {
         ("const bar = [[1],[2],[3]].flat()", None),
         ("const bar = [1,2,3].map(i => [i]).sort().flat()", None),
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(2)", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(2.0)", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(0.9999999999999999)", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(1.000000000000001)", None),
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(1, null)", None),
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(Infinity)", None),
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(Number.POSITIVE_INFINITY)", None),
@@ -117,11 +119,15 @@ fn test() {
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(+1)", None),
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(foo)", None),
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(foo.bar)", None),
-        ("const bar = [[1],[2],[3]].map(i => [i]).flat(1.00)", None),
     ];
 
     let fail = vec![
         ("const bar = [[1],[2],[3]].map(i => [i]).flat()", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(1)", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(1.0)", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(1.00)", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(0.99999999999999999)", None),
+        ("const bar = [[1],[2],[3]].map(i => [i]).flat(1.0000000000000001)", None),
         ("const bar = [[1],[2],[3]].map(i => [i]).flat(1,)", None),
         ("const bar = [1,2,3].map(i => [i]).flat()", None),
         ("const bar = [1,2,3].map((i) => [i]).flat()", None),

crates/oxc_linter/src/snapshots/unicorn_prefer_array_flat_map.snap

@@ -8,6 +8,41 @@ source: crates/oxc_linter/src/tester.rs
    ╰────
   help: Prefer `.flatMap(…)` over `.map(…).flat()`.
 
+  ⚠ eslint-plugin-unicorn(prefer-array-flat-map): `Array.flatMap` performs `Array.map` and `Array.flat` in one step.
+   ╭─[prefer_array_flat_map.tsx:1:13]
+ 1 │ const bar = [[1],[2],[3]].map(i => [i]).flat(1)
+   ·             ───────────────────────────────────
+   ╰────
+  help: Prefer `.flatMap(…)` over `.map(…).flat()`.
+
+  ⚠ eslint-plugin-unicorn(prefer-array-flat-map): `Array.flatMap` performs `Array.map` and `Array.flat` in one step.
+   ╭─[prefer_array_flat_map.tsx:1:13]
+ 1 │ const bar = [[1],[2],[3]].map(i => [i]).flat(1.0)
+   ·             ─────────────────────────────────────
+   ╰────
+  help: Prefer `.flatMap(…)` over `.map(…).flat()`.
+
+  ⚠ eslint-plugin-unicorn(prefer-array-flat-map): `Array.flatMap` performs `Array.map` and `Array.flat` in one step.
+   ╭─[prefer_array_flat_map.tsx:1:13]
+ 1 │ const bar = [[1],[2],[3]].map(i => [i]).flat(1.00)
+   ·             ──────────────────────────────────────
+   ╰────
+  help: Prefer `.flatMap(…)` over `.map(…).flat()`.
+
+  ⚠ eslint-plugin-unicorn(prefer-array-flat-map): `Array.flatMap` performs `Array.map` and `Array.flat` in one step.
+   ╭─[prefer_array_flat_map.tsx:1:13]
+ 1 │ const bar = [[1],[2],[3]].map(i => [i]).flat(0.99999999999999999)
+   ·             ─────────────────────────────────────────────────────
+   ╰────
+  help: Prefer `.flatMap(…)` over `.map(…).flat()`.
+
+  ⚠ eslint-plugin-unicorn(prefer-array-flat-map): `Array.flatMap` performs `Array.map` and `Array.flat` in one step.
+   ╭─[prefer_array_flat_map.tsx:1:13]
+ 1 │ const bar = [[1],[2],[3]].map(i => [i]).flat(1.0000000000000001)
+   ·             ────────────────────────────────────────────────────
+   ╰────
+  help: Prefer `.flatMap(…)` over `.map(…).flat()`.
+
   ⚠ eslint-plugin-unicorn(prefer-array-flat-map): `Array.flatMap` performs `Array.map` and `Array.flat` in one step.
    ╭─[prefer_array_flat_map.tsx:1:13]
  1 │ const bar = [[1],[2],[3]].map(i => [i]).flat(1,)