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fix(linter/unicorn): avoid prefer-array-find rest destructuring false positive #23654

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fix(linter/unicorn): avoid prefer-array-find rest destructuring false positive #23654

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30 changes: 23 additions & 7 deletions crates/oxc_linter/src/rules/unicorn/prefer_array_find.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,34 +26,40 @@ pub struct PreferArrayFind;
declare_oxc_lint!(
/// ### What it does
///
/// Encourages using `Array.prototype.find` instead of `filter(...)[0]` or
/// similar patterns when only the first matching element is needed.
/// Encourages using `Array.prototype.find` and `Array.prototype.findLast` instead of
/// taking the first or last matching element from `filter(...)`.
///
/// ### Why is this bad?
///
/// Using `filter(...)[0]` to get the first match is less efficient and more verbose
/// than using `find(...)`. `find` short-circuits when a match is found,
/// whereas `filter` evaluates the entire array.
/// Using `filter(...)[0]` or array destructuring to get the first match is less
/// efficient and more verbose than using `find(...)`. `find` and `findLast`
/// short-circuit when a match is found, whereas `filter` evaluates the entire array.
///
/// ### Examples
///
/// Examples of **incorrect** code for this rule:
/// ```js
/// const match = users.filter(u => u.id === id)[0];
/// const match = users.filter(fn).shift();
/// const [match] = users.filter(fn);
///
/// const match = users.filter(fn).at(-1);
/// const match = users.filter(fn).pop();
/// ```
///
/// Examples of **correct** code for this rule:
/// ```js
/// const match = users.find(u => u.id === id);
/// const match = users.find(fn);
///
/// const match = users.findLast(fn);
/// ```
PreferArrayFind,
unicorn,
perf, // Encourages more efficient use of built-in methods
pending,
version = "0.16.12",
short_description = "Encourages using `Array.prototype.find` instead of `filter(...)[0]` or similar patterns when only the first matching element is needed.",
short_description = "Encourages using `Array.prototype.find` and `Array.prototype.findLast` instead of taking the first or last matching element from `filter(...)`.",
);

impl Rule for PreferArrayFind {
Expand Down Expand Up @@ -131,6 +137,7 @@ impl Rule for PreferArrayFind {
if let BindingPattern::ArrayPattern(array_pat) = &var_decl.id
&& array_pat.elements.len() == 1
&& array_pat.elements[0].is_some()
&& array_pat.rest.is_none()
&& let Some(Expression::CallExpression(array_filter)) = &var_decl.init
&& is_filter_call(array_filter)
{
Expand Down Expand Up @@ -165,6 +172,7 @@ impl Rule for PreferArrayFind {
if let BindingPattern::ArrayPattern(array_pat) = &var_declarator.id
&& array_pat.elements.len() == 1
&& array_pat.elements[0].is_some()
&& array_pat.rest.is_none()
{
destructuring_nodes.push(reference);
}
Expand All @@ -174,7 +182,10 @@ impl Rule for PreferArrayFind {
if let AssignmentTarget::ArrayAssignmentTarget(target) =
&assignment_expr.left
{
if target.elements.len() == 1 && target.elements[0].is_some() {
if target.elements.len() == 1
&& target.elements[0].is_some()
&& target.rest.is_none()
{
destructuring_nodes.push(reference);
}
} else if let Some(
Expand Down Expand Up @@ -208,6 +219,7 @@ impl Rule for PreferArrayFind {
&assignment_expr.left
&& array_assignment_target.elements.len() == 1
&& array_assignment_target.elements[0].is_some()
&& array_assignment_target.rest.is_none()
&& let Expression::CallExpression(array_filter) = &assignment_expr.right
&& is_filter_call(array_filter)
{
Expand Down Expand Up @@ -290,6 +302,7 @@ fn test() {
"const [, foo] = array.filter(bar)",
"const [,] = array.filter(bar)",
"const [...foo] = array.filter(bar)",
"const [foo, ...rest] = array.filter(bar)",
"const [foo] = array.filter",
"const [foo] = filter(bar)",
// r#"const [foo] = array["filter"](bar)"#,
Expand All @@ -307,6 +320,7 @@ fn test() {
"[, foo] = array.filter(bar)",
"[,] = array.filter(bar)",
"[...foo] = array.filter(bar)",
"[foo, ...rest] = array.filter(bar)",
"[foo] = array.filter",
"[foo] = filter(bar)",
// r#"[foo] = array["filter"](bar)"#,
Expand Down Expand Up @@ -351,6 +365,8 @@ fn test() {
"const foo = array.filter(bar); [,] = foo;",
"const foo = array.filter(bar); const [...first] = foo;",
"const foo = array.filter(bar); [...first] = foo;",
"const foo = array.filter(bar); const [first, ...rest] = foo;",
"const foo = array.filter(bar); [first, ...rest] = foo;",
"const foo = array.filter(bar);
function a([bar] = foo) {}",
"const foo = array.filter; const first = foo[0]",
Expand Down
16 changes: 11 additions & 5 deletions tasks/website_linter/src/rules/snapshots/docs_rule_pages.snap
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Original file line number Diff line number Diff line change
Expand Up @@ -1436,27 +1436,33 @@ const source = `https://github.com/oxc-project/oxc/blob/${ data }/crates/oxc_lin

### What it does

Encourages using `Array.prototype.find` instead of `filter(...)[0]` or
similar patterns when only the first matching element is needed.
Encourages using `Array.prototype.find` and `Array.prototype.findLast` instead of
taking the first or last matching element from `filter(...)`.

### Why is this bad?

Using `filter(...)[0]` to get the first match is less efficient and more verbose
than using `find(...)`. `find` short-circuits when a match is found,
whereas `filter` evaluates the entire array.
Using `filter(...)[0]` or array destructuring to get the first match is less
efficient and more verbose than using `find(...)`. `find` and `findLast`
short-circuit when a match is found, whereas `filter` evaluates the entire array.

### Examples

Examples of **incorrect** code for this rule:
```js
const match = users.filter(u => u.id === id)[0];
const match = users.filter(fn).shift();
const [match] = users.filter(fn);

const match = users.filter(fn).at(-1);
const match = users.filter(fn).pop();
```

Examples of **correct** code for this rule:
```js
const match = users.find(u => u.id === id);
const match = users.find(fn);

const match = users.findLast(fn);
```


Expand Down
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