use oxc_ast::ast::Program;
use oxc_ast_visit::Visit;
use oxc_semantic::Semantic;
use crate::rules::{Rule, RuleFinding, RuleMeta, Severity};
pub struct NoIndexKey;
const RULE_META: RuleMeta = RuleMeta {
id: "no-index-key",
default_severity: Severity::Warning,
category: "react",
description: "Prefer stable IDs over array index as key",
};
impl Rule for NoIndexKey {
fn meta(&self) -> &RuleMeta {
&RULE_META
}
fn run(&self, program: &Program, _semantic: &Semantic, source_text: &str) -> Vec<RuleFinding> {
let mut collector = IndexKeyCollector {
findings: Vec::new(),
source: source_text,
};
collector.visit_program(program);
collector.findings
}
}
struct IndexKeyCollector<'a> {
findings: Vec<RuleFinding>,
source: &'a str,
}
impl<'a> Visit<'a> for IndexKeyCollector<'a> {
fn visit_jsx_opening_element(&mut self, el: &oxc_ast::ast::JSXOpeningElement<'a>) {
for attr_item in &el.attributes {
if let oxc_ast::ast::JSXAttributeItem::Attribute(attr) = attr_item {
let is_key = matches!(&attr.name, oxc_ast::ast::JSXAttributeName::Identifier(id) if id.name.as_str() == "key");
if !is_key {
continue;
}
if let Some(val) = &attr.value
&& let oxc_ast::ast::JSXAttributeValue::ExpressionContainer(container) = val
&& let oxc_ast::ast::JSXExpression::Identifier(ident) = &container.expression
&& ident.name.as_str() == "index"
{
let start = attr.span.start as usize;
let line = self.source[..start].lines().count().max(1);
let col = start - self.source[..start].rfind('\n').map(|i| i + 1).unwrap_or(0);
self.findings.push(RuleFinding {
line,
column: col + 1,
message: "Avoid using array index as `key` — prefer a stable ID"
.to_string(),
});
}
}
}
}
}