feat(linter) eslint-plugin-unicorn - text-encoding-identifier-case

crates/oxc_ast/src/visit.rs

@@ -1064,7 +1064,7 @@ pub trait Visit<'a>: Sized {
             }
             JSXAttributeValue::Element(elem) => self.visit_jsx_element(elem),
             JSXAttributeValue::Fragment(elem) => self.visit_jsx_fragment(elem),
-            JSXAttributeValue::StringLiteral(_) => {}
+            JSXAttributeValue::StringLiteral(lit) => self.visit_string_literal(lit),
         }
     }
 

crates/oxc_linter/src/rules.rs

@@ -145,6 +145,7 @@ mod unicorn {
     pub mod no_thenable;
     pub mod no_unnecessary_await;
     pub mod prefer_array_flat_map;
+    pub mod text_encoding_identifier_case;
     pub mod throw_new_error;
 }
 
@@ -255,6 +256,7 @@ oxc_macros::declare_all_lint_rules! {
     unicorn::no_instanceof_array,
     unicorn::no_unnecessary_await,
     unicorn::no_thenable,
+    unicorn::text_encoding_identifier_case,
     unicorn::throw_new_error,
     unicorn::prefer_array_flat_map,
     react::jsx_key,

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

@@ -0,0 +1,167 @@
+use oxc_ast::{
+    ast::{JSXAttributeItem, JSXAttributeName, JSXElementName},
+    AstKind,
+};
+use oxc_diagnostics::{
+    miette::{self, Diagnostic},
+    thiserror::{self, Error},
+};
+use oxc_macros::declare_oxc_lint;
+use oxc_semantic::AstNodeId;
+use oxc_span::{Atom, Span};
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `{1}` over `{2}`.")]
+#[diagnostic(severity(warning))]
+struct TextEncodingIdentifierCaseDiagnostic(#[label] pub Span, pub &'static str, pub Atom);
+
+#[derive(Debug, Default, Clone)]
+pub struct TextEncodingIdentifierCase;
+
+declare_oxc_lint!(
+    /// ### What it does
+    ///
+    /// This rule aims to enforce consistent case for text encoding identifiers.
+    ///
+    /// Enforces `'utf8'` for UTF-8 encoding
+    /// Enforces `'ascii'` for ASCII encoding.
+    ///
+    /// ### Example
+    /// ```javascript
+    /// // Fail
+    /// await fs.readFile(file, 'UTF-8');
+    ///
+    /// await fs.readFile(file, 'ASCII');
+    ///
+    /// const string = buffer.toString('utf-8');
+    ///
+    /// // pass
+    ///
+    /// await fs.readFile(file, 'utf8');
+    ///
+    /// await fs.readFile(file, 'ascii');
+    ///
+    /// const string = buffer.toString('utf8');
+    ///
+    /// ```
+    TextEncodingIdentifierCase,
+    style
+);
+
+impl Rule for TextEncodingIdentifierCase {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        let (str, span) = match node.kind() {
+            AstKind::StringLiteral(string_lit) => (&string_lit.value, string_lit.span),
+            AstKind::JSXText(jsx_text) => (&jsx_text.value, jsx_text.span),
+            _ => {
+                return;
+            }
+        };
+
+        if str.as_str() == "utf-8" && is_jsx_meta_elem_with_charset_attr(node.id(), ctx) {
+            return;
+        }
+
+        let Some(replacement) = get_replacement(str) else {
+            return;
+        };
+
+        if replacement == str.as_str() {
+            return;
+        }
+
+        ctx.diagnostic(TextEncodingIdentifierCaseDiagnostic(span, replacement, str.clone()));
+    }
+}
+
+fn get_replacement(node: &Atom) -> Option<&'static str> {
+    if !matches!(node.as_str().len(), 4 | 5) {
+        return None;
+    }
+
+    let node_lower = node.as_str().to_ascii_lowercase();
+
+    if node_lower == "utf-8" || node_lower == "utf8" {
+        return Some("utf8");
+    }
+
+    if node_lower == "ascii" {
+        return Some("ascii");
+    }
+
+    None
+}
+
+fn is_jsx_meta_elem_with_charset_attr(id: AstNodeId, ctx: &LintContext) -> bool {
+    let Some(parent) = ctx.nodes().parent_node(id) else { return false };
+
+    let AstKind::JSXAttributeItem(JSXAttributeItem::Attribute(jsx_attr)) = parent.kind() else {
+        return false;
+    };
+
+    let JSXAttributeName::Identifier(ident) = &jsx_attr.name else { return false };
+    if ident.name.to_lowercase() != "charset" {
+        return false;
+    }
+
+    let Some(AstKind::JSXOpeningElement(opening_elem)) = ctx.nodes().parent_kind(parent.id())
+    else {
+        return false;
+    };
+
+    let JSXElementName::Identifier(name) = &opening_elem.name else { return false };
+
+    if name.name.to_lowercase() != "meta" {
+        return false;
+    }
+
+    true
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        r#"`UTF-8`"#,
+        r#""utf8""#,
+        r#""utf+8""#,
+        r#""   utf8   ""#,
+        "\'utf8\'",
+        r#""\\u0055tf8""#,
+        r#"const ASCII = 1"#,
+        r#"const UTF8 = 1"#,
+        r#"<meta charset="utf-8" />"#,
+        r#"<META CHARSET="utf-8" />"#,
+    ];
+
+    let fail = vec![
+        r#""UTF-8""#,
+        r#""utf-8""#,
+        r#"'utf-8'"#,
+        r#""Utf8""#,
+        r#""ASCII""#,
+        r#"fs.readFile?.(file, "UTF-8")"#,
+        r#"fs?.readFile(file, "UTF-8")"#,
+        r#"readFile(file, "UTF-8")"#,
+        r#"fs.readFile(...file, "UTF-8")"#,
+        r#"new fs.readFile(file, "UTF-8")"#,
+        r#"fs.readFile(file, {encoding: "UTF-8"})"#,
+        r#"fs.readFile("UTF-8")"#,
+        r#"fs.readFile(file, "UTF-8", () => {})"#,
+        r#"fs.readFileSync(file, "UTF-8")"#,
+        r#"fs[readFile](file, "UTF-8")"#,
+        r#"fs["readFile"](file, "UTF-8")"#,
+        r#"await fs.readFile(file, "UTF-8",)"#,
+        r#"fs.promises.readFile(file, "UTF-8",)"#,
+        r#"whatever.readFile(file, "UTF-8",)"#,
+        r#"<not-meta charset="utf-8" />"#,
+        r#"<meta not-charset="utf-8" />"#,
+        r#"<meta charset="ASCII" />"#,
+        r#"<META CHARSET="ASCII" />"#,
+    ];
+
+    Tester::new_without_config(TextEncodingIdentifierCase::NAME, pass, fail).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/text_encoding_identifier_case.snap

@@ -0,0 +1,143 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: text_encoding_identifier_case
+---
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ "UTF-8"
+   · ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `utf-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ "utf-8"
+   · ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `utf-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ 'utf-8'
+   · ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `Utf8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ "Utf8"
+   · ──────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `ascii` over `ASCII`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ "ASCII"
+   · ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs.readFile?.(file, "UTF-8")
+   ·                     ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs?.readFile(file, "UTF-8")
+   ·                    ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ readFile(file, "UTF-8")
+   ·                ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs.readFile(...file, "UTF-8")
+   ·                      ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ new fs.readFile(file, "UTF-8")
+   ·                       ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs.readFile(file, {encoding: "UTF-8"})
+   ·                              ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs.readFile("UTF-8")
+   ·             ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs.readFile(file, "UTF-8", () => {})
+   ·                   ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs.readFileSync(file, "UTF-8")
+   ·                       ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs[readFile](file, "UTF-8")
+   ·                    ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs["readFile"](file, "UTF-8")
+   ·                      ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ await fs.readFile(file, "UTF-8",)
+   ·                         ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ fs.promises.readFile(file, "UTF-8",)
+   ·                            ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `UTF-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ whatever.readFile(file, "UTF-8",)
+   ·                         ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `utf-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ <not-meta charset="utf-8" />
+   ·                   ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `utf8` over `utf-8`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ <meta not-charset="utf-8" />
+   ·                   ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `ascii` over `ASCII`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ <meta charset="ASCII" />
+   ·               ───────
+   ╰────
+
+  ⚠ eslint-plugin-unicorn(text-encoding-identifier-case): Prefer `ascii` over `ASCII`.
+   ╭─[text_encoding_identifier_case.tsx:1:1]
+ 1 │ <META CHARSET="ASCII" />
+   ·               ───────
+   ╰────
+
+