feat(linter/eslint): Implement no-multi-str (#4038)

Rule Detail:
[link](https://eslint.org/docs/latest/rules/no-multi-str)

---------

Co-authored-by: wenzhe <mysteryven@gmail.com>

Author: jelly

crates/oxc_linter/src/rules.rs

@@ -76,6 +76,7 @@ mod eslint {
     pub mod no_irregular_whitespace;
     pub mod no_iterator;
     pub mod no_loss_of_precision;
+    pub mod no_multi_str;
     pub mod no_new;
     pub mod no_new_native_nonconstructor;
     pub mod no_new_wrappers;
@@ -449,6 +450,7 @@ oxc_macros::declare_all_lint_rules! {
     eslint::no_caller,
     eslint::no_case_declarations,
     eslint::no_class_assign,
+    eslint::no_multi_str,
     eslint::require_await,
     eslint::no_compare_neg_zero,
     eslint::no_cond_assign,

crates/oxc_linter/src/rules/eslint/no_multi_str.rs

@@ -0,0 +1,78 @@
+use oxc_ast::AstKind;
+use oxc_diagnostics::OxcDiagnostic;
+use oxc_macros::declare_oxc_lint;
+use oxc_span::Span;
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+fn no_multi_str_diagnostic(span0: Span) -> OxcDiagnostic {
+    OxcDiagnostic::warn("eslint(no-multi-str): Unexpected multi string.").with_label(span0)
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct NoMultiStr;
+
+declare_oxc_lint!(
+    /// ### What it does
+    ///
+    /// Disallow multiline strings.
+    ///
+    /// ### Why is this bad?
+    ///
+    /// Some consider this to be a bad practice as it was an undocumented feature of JavaScript
+    /// that was only formalized later.
+    ///
+    /// ### Example
+    /// ```javascript
+    /// var x = "Line 1 \
+    ///  Line 2";
+    /// ```
+    NoMultiStr,
+    style,
+);
+
+impl Rule for NoMultiStr {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        if let AstKind::StringLiteral(literal) = node.kind() {
+            let source = literal.span.source_text(ctx.source_text());
+            // https://github.com/eslint/eslint/blob/9e6d6405c3ee774c2e716a3453ede9696ced1be7/lib/shared/ast-utils.js#L12
+            let position =
+                source.find(|ch| matches!(ch, '\r' | '\n' | '\u{2028}' | '\u{2029}')).unwrap_or(0);
+            if position != 0 {
+                // We found the "newline" character but want to highlight the '\', so go back one
+                // character.
+                let multi_span_start =
+                    literal.span.start + u32::try_from(position).unwrap_or_default() - 1;
+                ctx.diagnostic(no_multi_str_diagnostic(Span::new(
+                    multi_span_start,
+                    multi_span_start + 1,
+                )));
+            }
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "var a = 'Line 1 Line 2';",
+        "var a = <div>
+			<h1>Wat</h1>
+			</div>;", // { "ecmaVersion": 6, "parserOptions": { "ecmaFeatures": { "jsx": true } } }
+    ];
+
+    let fail = vec![
+        "var x = 'Line 1 \\
+			 Line 2'",
+        "test('Line 1 \\
+			 Line 2');",
+        "'foo\\\rbar';",
+        "'foo\\
bar';",
+        "'foo\\
ar';",
+        "'\\
still fails';",
+    ];
+
+    Tester::new(NoMultiStr::NAME, pass, fail).test_and_snapshot();
+}

crates/oxc_linter/src/snapshots/no_multi_str.snap

@@ -0,0 +1,40 @@
+---
+source: crates/oxc_linter/src/tester.rs
+---
+  ⚠ eslint(no-multi-str): Unexpected multi string.
+   ╭─[no_multi_str.tsx:1:17]
+ 1 │ var x = 'Line 1 \
+   ·                 ─
+ 2 │              Line 2'
+   ╰────
+
+  ⚠ eslint(no-multi-str): Unexpected multi string.
+   ╭─[no_multi_str.tsx:1:14]
+ 1 │ test('Line 1 \
+   ·              ─
+ 2 │              Line 2');
+   ╰────
+
+  ⚠ eslint(no-multi-str): Unexpected multi string.
+   ╭─[no_multi_str.tsx:1:5]
+ 1 │ 'foo\bar';
+   ·     ─
+   ╰────
+
+  ⚠ eslint(no-multi-str): Unexpected multi string.
+   ╭─[no_multi_str.tsx:1:5]
+ 1 │ 'foo\
bar';
+   ·     ─
+   ╰────
+
+  ⚠ eslint(no-multi-str): Unexpected multi string.
+   ╭─[no_multi_str.tsx:1:5]
+ 1 │ 'foo\
ar';
+   ·     ─
+   ╰────
+
+  ⚠ eslint(no-multi-str): Unexpected multi string.
+   ╭─[no_multi_str.tsx:1:2]
+ 1 │ '\
still fails';
+   ·  ─
+   ╰────