From 4763941ce22508dbc8a24e3f66be847161eec2a4 Mon Sep 17 00:00:00 2001
From: therewillbecode <tomw08@gmail.com>
Date: Mon, 17 Feb 2025 20:52:32 +0000
Subject: [PATCH] Add correctness examples to no-sparse-arrays eslint rule

---
 .../src/rules/eslint/no_sparse_arrays.rs      | 36 +++++++++++++++++--
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/crates/oxc_linter/src/rules/eslint/no_sparse_arrays.rs b/crates/oxc_linter/src/rules/eslint/no_sparse_arrays.rs
index e102fcc62fe07..09affda8890b3 100644
--- a/crates/oxc_linter/src/rules/eslint/no_sparse_arrays.rs
+++ b/crates/oxc_linter/src/rules/eslint/no_sparse_arrays.rs
@@ -14,13 +14,43 @@ declare_oxc_lint!(
     ///
     /// ### Why is this bad?
     ///
-    /// The confusion around sparse arrays is enough that it’s recommended to avoid using them unless you are certain that they are useful in your code.
+    /// Take the following example:
     ///
-    /// ### Example
+    /// ```javascript
+    /// const items = [,,];
+    /// ```
+    ///
+    /// While the items array in this example has a length of 2, there are actually
+    /// no values in items[0] or items[1]. The fact that the array literal is
+    /// valid with only commas inside, coupled with the length being set and
+    /// actual item values not being set, make sparse arrays confusing for many
+    /// developers.
+    ///
+    /// The confusion around sparse arrays is enough that it’s recommended to
+    /// avoid using them unless you are certain that they are useful in your
+    /// code.
+    ///
+    ///
+    /// ### Examples
+    ///
+    /// Examples of **incorrect** code for this rule:
     /// ```javascript
     /// var items = [,,];
+    /// ```
+    ///
+    /// ```javascript
     /// var colors = [ "red",, "blue" ];
     /// ```
+    ///
+    /// Examples of **correct** code for this rule:
+    /// ```javascript
+    /// var items = [];
+    /// ```
+    ///
+    /// // trailing comma (after the last element) is not a problem
+    /// ```javascript
+    /// var colors = [ "red", "blue", ];
+    /// ```
     NoSparseArrays,
     eslint,
     correctness
@@ -79,7 +109,7 @@ impl Rule for NoSparseArrays {
 fn test() {
     use crate::tester::Tester;
 
-    let pass = vec!["var a = [ 1, 2, ]"];
+    let pass = vec!["var a = [ 1, 2, ]", "var a = [];"];
 
     let fail = vec![
         "var a = [,];",