feat(linter): implement unicorn/prefer-string-raw lint rule (#7335)

Implements
[unicorn/refer-string-raw](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/prefer-string-raw.md)
for #684

crates/oxc_linter/src/rules.rs

@@ -358,6 +358,7 @@ mod unicorn {
     pub mod prefer_regexp_test;
     pub mod prefer_set_size;
     pub mod prefer_spread;
+    pub mod prefer_string_raw;
     pub mod prefer_string_replace_all;
     pub mod prefer_string_slice;
     pub mod prefer_string_starts_ends_with;
@@ -946,6 +947,7 @@ oxc_macros::declare_all_lint_rules! {
     unicorn::prefer_regexp_test,
     unicorn::prefer_set_size,
     unicorn::prefer_spread,
+    unicorn::prefer_string_raw,
     unicorn::prefer_string_replace_all,
     unicorn::prefer_string_slice,
     unicorn::prefer_string_starts_ends_with,

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

@@ -0,0 +1,283 @@
+use oxc_ast::{
+    ast::{JSXAttributeValue, PropertyKey, TSEnumMemberName},
+    AstKind,
+};
+use oxc_diagnostics::OxcDiagnostic;
+use oxc_ecmascript::StringCharAt;
+use oxc_macros::declare_oxc_lint;
+use oxc_span::Span;
+use oxc_syntax::keyword::RESERVED_KEYWORDS;
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+fn prefer_string_raw(span: Span) -> OxcDiagnostic {
+    OxcDiagnostic::warn(r"`String.raw` should be used to avoid escaping `\`.").with_label(span)
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct PreferStringRaw;
+
+declare_oxc_lint!(
+    /// ### What it does
+    ///
+    /// Prefers use of String.raw to avoid escaping \.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// Excessive backslashes can make string values less readable which can be avoided by using `String.raw`.
+    ///
+    /// ### Example
+    ///
+    /// Examples of **incorrect** code for this rule:
+    /// ```javascript
+    /// const file = "C:\\windows\\style\\path\\to\\file.js";
+    /// const regexp = new RegExp('foo\\.bar');
+    /// ```
+    ///
+    /// Examples of **correct** code for this rule:
+    /// ```javascript
+    /// const file = String.raw`C:\windows\style\path\to\file.js`;
+    /// const regexp = new RegExp(String.raw`foo\.bar`);
+    /// ```
+    PreferStringRaw,
+    style,
+    fix,
+);
+
+fn unescape_backslash(input: &str, quote: char) -> String {
+    let mut result = String::with_capacity(input.len());
+    let mut chars = input.chars().peekable();
+
+    while let Some(c) = chars.next() {
+        if c == '\\' {
+            if let Some(next) = chars.peek() {
+                if *next == '\\' || *next == quote {
+                    result.push(*next);
+                    chars.next();
+                    continue;
+                }
+            }
+        }
+
+        result.push(c);
+    }
+
+    result
+}
+
+impl Rule for PreferStringRaw {
+    #[allow(clippy::cast_precision_loss)]
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        let AstKind::StringLiteral(string_literal) = node.kind() else {
+            return;
+        };
+
+        let parent_node = ctx.nodes().parent_node(node.id());
+
+        if let Some(parent_node) = parent_node {
+            match parent_node.kind() {
+                AstKind::Directive(_) => {
+                    return;
+                }
+                AstKind::ImportDeclaration(decl) => {
+                    if string_literal.span == decl.source.span {
+                        return;
+                    }
+                }
+                AstKind::ExportNamedDeclaration(decl) => {
+                    if let Some(source) = &decl.source {
+                        if string_literal.span == source.span {
+                            return;
+                        }
+                    }
+                }
+                AstKind::ExportAllDeclaration(decl) => {
+                    if string_literal.span == decl.source.span {
+                        return;
+                    }
+                }
+                AstKind::ObjectProperty(prop) => {
+                    let PropertyKey::StringLiteral(key) = &prop.key else {
+                        return;
+                    };
+
+                    if !prop.computed && string_literal.span == key.span {
+                        return;
+                    }
+                }
+                AstKind::PropertyKey(_) => {
+                    if let Some(AstKind::ObjectProperty(prop)) =
+                        ctx.nodes().parent_node(parent_node.id()).map(AstNode::kind)
+                    {
+                        let PropertyKey::StringLiteral(key) = &prop.key else {
+                            return;
+                        };
+
+                        if !prop.computed && key.span == string_literal.span {
+                            return;
+                        }
+                    }
+                }
+                AstKind::JSXAttributeItem(attr) => {
+                    let Some(attr) = attr.as_attribute() else {
+                        return;
+                    };
+
+                    let Some(JSXAttributeValue::StringLiteral(value)) = &attr.value else {
+                        return;
+                    };
+
+                    if value.span == string_literal.span {
+                        return;
+                    }
+                }
+                AstKind::TSEnumMember(member) => {
+                    if member.span == string_literal.span {
+                        return;
+                    };
+
+                    let TSEnumMemberName::String(id) = &member.id else {
+                        return;
+                    };
+
+                    if id.span == string_literal.span {
+                        return;
+                    }
+                }
+                _ => {}
+            }
+        }
+
+        let raw = ctx.source_range(string_literal.span);
+
+        let last_char_index = raw.len() - 2;
+        if raw.char_at(Some(last_char_index as f64)) == Some('\\') {
+            return;
+        }
+
+        if !raw.contains(r"\\") || raw.contains('`') || raw.contains("${") {
+            return;
+        }
+
+        let Some(quote) = raw.char_at(Some(0.0)) else {
+            return;
+        };
+
+        let trimmed = ctx.source_range(string_literal.span.shrink(1));
+
+        let unescaped = unescape_backslash(trimmed, quote);
+
+        if unescaped != string_literal.value.as_ref() {
+            return;
+        }
+
+        ctx.diagnostic_with_fix(prefer_string_raw(string_literal.span), |fixer| {
+            let end = string_literal.span.start;
+            let before = ctx.source_range(oxc_span::Span::new(0, end));
+
+            let mut fix = format!("String.raw`{unescaped}`");
+
+            if ends_with_keyword(before) {
+                fix = format!(" {fix}");
+            }
+
+            fixer.replace(string_literal.span, fix)
+        });
+    }
+}
+
+fn ends_with_keyword(source: &str) -> bool {
+    for keyword in &RESERVED_KEYWORDS {
+        if source.ends_with(keyword) {
+            return true;
+        }
+    }
+
+    if source.ends_with("of") {
+        return true;
+    }
+
+    false
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass: Vec<&str> = vec![
+        r"const file = String.raw`C:\windows\style\path\to\file.js`;",
+        r"const regexp = new RegExp(String.raw`foo\.bar`);",
+        r"a = '\''",
+        r"'a\\b'",
+        r#"import foo from "./foo\\bar.js";"#,
+        r#"export {foo} from "./foo\\bar.js";"#,
+        r#"export * from "./foo\\bar.js";"#,
+        r"a = {'a\\b': 1}",
+        "
+            a = '\\\\a \\
+                b'
+         ",
+        r"a = 'a\\b\u{51}c'",
+        "a = 'a\\\\b`'",
+        "a = 'a\\\\b${foo}'",
+        r#"<Component attribute="a\\b" />"#,
+        r#"
+             enum Files {
+                Foo = "C:\\\\path\\\\to\\\\foo.js",
+             }
+        "#,
+        r#"
+             enum Foo {
+                "\\\\a\\\\b" = "baz",
+             }
+        "#,
+        r"const a = 'a\\';",
+    ];
+
+    let fail = vec![
+        r#"const file = "C:\\windows\\style\\path\\to\\file.js";"#,
+        r"const regexp = new RegExp('foo\\.bar');",
+        r"a = 'a\\b'",
+        r"a = {['a\\b']: b}",
+        r"function a() {return'a\\b'}",
+        r"function* a() {yield'a\\b'}",
+        r"function a() {throw'a\\b'}",
+        r"if (typeof'a\\b' === 'string') {}",
+        r"const a = () => void'a\\b';",
+        r"const foo = 'foo \\x46';",
+        r"for (const f of'a\\b') {}",
+    ];
+
+    let fix = vec![
+        (
+            r#"const file = "C:\\windows\\style\\path\\to\\file.js";"#,
+            r"const file = String.raw`C:\windows\style\path\to\file.js`;",
+            None,
+        ),
+        (
+            r"const regexp = new RegExp('foo\\.bar');",
+            r"const regexp = new RegExp(String.raw`foo\.bar`);",
+            None,
+        ),
+        (r"a = 'a\\b'", r"a = String.raw`a\b`", None),
+        (r"a = {['a\\b']: b}", r"a = {[String.raw`a\b`]: b}", None),
+        (r"function a() {return'a\\b'}", r"function a() {return String.raw`a\b`}", None),
+        (r"const foo = 'foo \\x46';", r"const foo = String.raw`foo \x46`;", None),
+        (r"for (const f of'a\\b') {}", r"for (const f of String.raw`a\b`) {}", None),
+        (r"a = 'a\\b'", r"a = String.raw`a\b`", None),
+        (r"a = {['a\\b']: b}", r"a = {[String.raw`a\b`]: b}", None),
+        (r"function a() {return'a\\b'}", r"function a() {return String.raw`a\b`}", None),
+        (r"function* a() {yield'a\\b'}", r"function* a() {yield String.raw`a\b`}", None),
+        (r"function a() {throw'a\\b'}", r"function a() {throw String.raw`a\b`}", None),
+        (
+            r"if (typeof'a\\b' === 'string') {}",
+            r"if (typeof String.raw`a\b` === 'string') {}",
+            None,
+        ),
+        (r"const a = () => void'a\\b';", r"const a = () => void String.raw`a\b`;", None),
+        (r"const foo = 'foo \\x46';", r"const foo = String.raw`foo \x46`;", None),
+        (r"for (const f of'a\\b') {}", r"for (const f of String.raw`a\b`) {}", None),
+    ];
+
+    Tester::new(PreferStringRaw::NAME, pass, fail).expect_fix(fix).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/prefer_string_raw.snap

@@ -0,0 +1,80 @@
+---
+source: crates/oxc_linter/src/tester.rs
+snapshot_kind: text
+---
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:14]
+ 1 │ const file = "C:\\windows\\style\\path\\to\\file.js";
+   ·              ───────────────────────────────────────
+   ╰────
+  help: Replace `"C:\\windows\\style\\path\\to\\file.js"` with `String.raw`C:\windows\style\path\to\file.js``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:27]
+ 1 │ const regexp = new RegExp('foo\\.bar');
+   ·                           ───────────
+   ╰────
+  help: Replace `'foo\\.bar'` with `String.raw`foo\.bar``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:5]
+ 1 │ a = 'a\\b'
+   ·     ──────
+   ╰────
+  help: Replace `'a\\b'` with `String.raw`a\b``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:7]
+ 1 │ a = {['a\\b']: b}
+   ·       ──────
+   ╰────
+  help: Replace `'a\\b'` with `String.raw`a\b``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:21]
+ 1 │ function a() {return'a\\b'}
+   ·                     ──────
+   ╰────
+  help: Replace `'a\\b'` with ` String.raw`a\b``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:21]
+ 1 │ function* a() {yield'a\\b'}
+   ·                     ──────
+   ╰────
+  help: Replace `'a\\b'` with ` String.raw`a\b``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:20]
+ 1 │ function a() {throw'a\\b'}
+   ·                    ──────
+   ╰────
+  help: Replace `'a\\b'` with ` String.raw`a\b``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:11]
+ 1 │ if (typeof'a\\b' === 'string') {}
+   ·           ──────
+   ╰────
+  help: Replace `'a\\b'` with ` String.raw`a\b``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:21]
+ 1 │ const a = () => void'a\\b';
+   ·                     ──────
+   ╰────
+  help: Replace `'a\\b'` with ` String.raw`a\b``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:13]
+ 1 │ const foo = 'foo \\x46';
+   ·             ───────────
+   ╰────
+  help: Replace `'foo \\x46'` with `String.raw`foo \x46``.
+
+  ⚠ eslint-plugin-unicorn(prefer-string-raw): `String.raw` should be used to avoid escaping `\`.
+   ╭─[prefer_string_raw.tsx:1:16]
+ 1 │ for (const f of'a\\b') {}
+   ·                ──────
+   ╰────
+  help: Replace `'a\\b'` with ` String.raw`a\b``.