feat(lint/js): add noReactStringRefs

.changeset/fifty-chicken-like.md

@@ -0,0 +1,7 @@
+---
+"@biomejs/biome": patch
+---
+
+Added the new nursery rule [`noReactStringRefs`](https://biomejs.dev/linter/rules/no-react-string-refs/), which disallows legacy React string refs such as `ref="hello"` and `this.refs.hello`.
+
+Biome also reports template-literal refs such as ``ref={`hello`}``, so React code can consistently migrate to callback refs, `createRef()`, or `useRef()`.

crates/biome_js_analyze/src/lint/nursery/no_react_string_refs.rs

@@ -0,0 +1,199 @@
+use std::sync::Arc;
+
+use camino::Utf8PathBuf;
+
+use crate::react::components::{AnyPotentialReactComponentDeclaration, ReactComponentInfo};
+use crate::services::semantic::Semantic;
+use biome_analyze::{
+    Rule, RuleDiagnostic, RuleDomain, RuleSource, context::RuleContext, declare_lint_rule,
+};
+use biome_console::markup;
+use biome_diagnostics::Severity;
+use biome_js_syntax::{
+    AnyJsExpression, AnyJsMemberExpression, AnyJsTemplateElement, AnyJsxAttributeValue,
+    JsxAttribute,
+};
+use biome_package::PackageJson;
+use biome_rowan::{AstNode, TextRange, declare_node_union};
+use biome_rule_options::no_react_string_refs::NoReactStringRefsOptions;
+
+declare_lint_rule! {
+    /// Disallow string refs in React components.
+    ///
+    /// String refs are a legacy React feature. Modern React code should use callback refs,
+    /// `createRef()`, or `useRef()` instead.
+    ///
+    /// Biome also flags template literal refs, even though upstream only does so through an option.
+    ///
+    /// ## Examples
+    ///
+    /// ### Invalid
+    ///
+    /// ```jsx,expect_diagnostic
+    /// function Hello() {
+    ///   return <div ref="hello">Hello</div>;
+    /// }
+    /// ```
+    ///
+    /// ```jsx,expect_diagnostic
+    /// function Hello({ id }) {
+    ///   return <div ref={`hello-${id}`}>Hello</div>;
+    /// }
+    /// ```
+    ///
+    /// ```jsx,expect_diagnostic
+    /// class Hello extends React.Component {
+    ///   componentDidMount() {
+    ///     this.refs.hello.focus();
+    ///   }
+    /// }
+    /// ```
+    ///
+    /// ### Valid
+    ///
+    /// ```jsx
+    /// function Hello() {
+    ///   const helloRef = useRef(null);
+    ///   return <div ref={helloRef}>Hello</div>;
+    /// }
+    /// ```
+    ///
+    pub NoReactStringRefs {
+        version: "next",
+        name: "noReactStringRefs",
+        language: "js",
+        sources: &[RuleSource::EslintReact("no-string-refs").same()],
+        domains: &[RuleDomain::React],
+        recommended: true,
+        severity: Severity::Warning,
+    }
+}
+
+declare_node_union! {
+    pub AnyNoReactStringRefsQuery = JsxAttribute | AnyJsMemberExpression
+}
+
+pub enum NoReactStringRefsState {
+    RefAttribute(TextRange),
+    ThisRefs(TextRange),
+}
+
+impl Rule for NoReactStringRefs {
+    type Query = Semantic<AnyNoReactStringRefsQuery>;
+    type State = NoReactStringRefsState;
+    type Signals = Option<Self::State>;
+    type Options = NoReactStringRefsOptions;
+
+    fn run(ctx: &RuleContext<Self>) -> Self::Signals {
+        match ctx.query() {
+            AnyNoReactStringRefsQuery::JsxAttribute(attribute) => {
+                let name = attribute.name().ok()?;
+                let name = name.as_jsx_name()?;
+                if name.value_token().ok()?.text_trimmed() != "ref" {
+                    return None;
+                }
+
+                let value = attribute.initializer()?.value().ok()?;
+                is_string_ref_value(&value)
+                    .then_some(NoReactStringRefsState::RefAttribute(value.range()))
+            }
+            AnyNoReactStringRefsQuery::AnyJsMemberExpression(member_expression) => {
+                if is_react_18_3_or_higher(ctx) {
+                    return None;
+                }
+
+                let refs_range = this_refs_range(member_expression)?;
+
+                member_expression
+                    .syntax()
+                    .ancestors()
+                    .filter_map(AnyPotentialReactComponentDeclaration::cast)
+                    .find_map(|declaration| {
+                        ReactComponentInfo::from_declaration(declaration.syntax())
+                    })
+                    .map(|_| NoReactStringRefsState::ThisRefs(refs_range))
+            }
+        }
+    }
+
+    fn diagnostic(_ctx: &RuleContext<Self>, state: &Self::State) -> Option<RuleDiagnostic> {
+        let (range, message, note, help) = match state {
+            NoReactStringRefsState::RefAttribute(range) => (
+                *range,
+                markup! { "String refs are deprecated." },
+                markup! {
+                    "String refs are a legacy React feature that can make ref usage harder to follow."
+                },
+                markup! {
+                    "Use a callback ref or an object ref created with "<Emphasis>"createRef()"</Emphasis>" or "<Emphasis>"useRef()"</Emphasis>" instead."
+                },
+            ),
+            NoReactStringRefsState::ThisRefs(range) => (
+                *range,
+                markup! { "Using "<Emphasis>"this.refs"</Emphasis>" is deprecated." },
+                markup! {
+                    "Accessing refs through "<Emphasis>"this.refs"</Emphasis>" relies on React's legacy string ref behavior."
+                },
+                markup! {
+                    "Store the ref on an instance field with a callback ref, or switch to "<Emphasis>"createRef()"</Emphasis>" or "<Emphasis>"useRef()"</Emphasis>"."
+                },
+            ),
+        };
+
+        Some(
+            RuleDiagnostic::new(rule_category!(), range, message)
+                .note(note)
+                .note(help),
+        )
+    }
+}
+
+/// Check if the attribute value is a string ref, which can be either a string literal or a template literal with only string chunks.
+fn is_string_ref_value(value: &AnyJsxAttributeValue) -> bool {
+    match value {
+        AnyJsxAttributeValue::AnyJsxTag(_) => false,
+        AnyJsxAttributeValue::JsxString(_) => true,
+        AnyJsxAttributeValue::JsxExpressionAttributeValue(expression) => {
+            match expression.expression().ok() {
+                Some(AnyJsExpression::AnyJsLiteralExpression(literal)) => {
+                    literal.as_js_string_literal_expression().is_some()
+                }
+                Some(AnyJsExpression::JsTemplateExpression(template)) => {
+                    template.elements().into_iter().any(|element| {
+                        matches!(
+                            element,
+                            AnyJsTemplateElement::JsTemplateChunkElement(_)
+                                | AnyJsTemplateElement::JsTemplateElement(_)
+                        )
+                    })
+                }
+                _ => false,
+            }
+        }
+    }
+}
+
+fn is_react_18_3_or_higher(ctx: &RuleContext<NoReactStringRefs>) -> bool {
+    ctx.get_service::<Option<(Utf8PathBuf, Arc<PackageJson>)>>()
+        .and_then(|manifest| {
+            manifest
+                .as_ref()
+                .map(|(_, package_json)| package_json.matches_dependency("react", ">=18.3.0"))
+        })
+        == Some(true)
+}
+
+/// Returns `Some` if the member expression is `this.refs`, otherwise `None`.
+fn this_refs_range(member_expression: &AnyJsMemberExpression) -> Option<TextRange> {
+    if member_expression
+        .object()
+        .ok()?
+        .as_js_this_expression()
+        .is_some()
+        && member_expression.member_name()?.text() == "refs"
+    {
+        return Some(member_expression.range());
+    }
+
+    None
+}

crates/biome_js_analyze/tests/specs/nursery/noReactStringRefs/invalid.jsx

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+/* should generate diagnostics */
+import React from "react";
+
+class StringRefs extends React.Component {
+	componentDidMount() {
+		this.refs.hello.focus();
+		this.refs["world"]?.focus();
+	}
+
+	render() {
+		return (
+			<section>
+				<div ref="hello">Hello</div>
+				<div ref={"world"}>World</div>
+				<div ref={`template`}>Template</div>
+				<div ref={`template-${id}`}>Template Expression</div>
+			</section>
+		);
+	}
+}