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fix: escape non-ASCII characters as \uNNNN in string literals #11

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Merged
Brooooooklyn merged 1 commit into from
Feb 5, 2026
Merged

fix: escape non-ASCII characters as \uNNNN in string literals #11

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105 changes: 80 additions & 25 deletions crates/oxc_angular_compiler/src/output/emitter.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1227,9 +1227,11 @@ fn is_nullish_coalesce(expr: &OutputExpression<'_>) -> bool {
/// Escape a string for JavaScript output.
///
/// Uses double quotes to match Angular's output style.
/// Only escapes control characters (`"`, `\`, `\n`, `\r`, and `$` when requested).
/// Non-ASCII printable characters (e.g. `×`, `é`, `α`) are emitted as literal UTF-8,
/// matching Angular's `escapeIdentifier` behavior.
/// Escapes `"`, `\`, `\n`, `\r`, `$` (when requested), ASCII control characters,
/// and all non-ASCII characters (code point > 0x7E) as `\uNNNN` sequences.
/// Characters above the BMP (U+10000+) are encoded as UTF-16 surrogate pairs
/// (`\uXXXX\uXXXX`). This matches TypeScript's emitter behavior, which escapes
/// non-ASCII characters in string literals.
fn escape_string(input: &str, escape_dollar: bool) -> String {
let mut result = String::with_capacity(input.len() + 2);
result.push('"');
Expand All @@ -1240,19 +1242,37 @@ fn escape_string(input: &str, escape_dollar: bool) -> String {
'\n' => result.push_str("\\n"),
'\r' => result.push_str("\\r"),
'$' if escape_dollar => result.push_str("\\$"),
// Escape ASCII control characters (0x00-0x1F, 0x7F) other than \n and \r
c if c.is_ascii_control() => {
// ASCII printable characters (0x20-0x7E) are emitted literally
c if (' '..='\x7E').contains(&c) => result.push(c),
// Everything else (ASCII control chars, non-ASCII) is escaped as \uNNNN.
// Characters above the BMP are encoded as UTF-16 surrogate pairs.
c => {
let code = c as u32;
result.push_str(&format!("\\u{code:04X}"));
if code <= 0xFFFF {
push_unicode_escape(&mut result, code);
} else {
let hi = 0xD800 + ((code - 0x10000) >> 10);
let lo = 0xDC00 + ((code - 0x10000) & 0x3FF);
push_unicode_escape(&mut result, hi);
push_unicode_escape(&mut result, lo);
}
}
// All other characters (including non-ASCII printable) are emitted literally
_ => result.push(c),
}
}
result.push('"');
result
}

/// Push a `\uXXXX` escape sequence for a 16-bit code unit.
fn push_unicode_escape(buf: &mut String, code: u32) {
const HEX: &[u8; 16] = b"0123456789ABCDEF";
buf.push_str("\\u");
buf.push(HEX[((code >> 12) & 0xF) as usize] as char);
buf.push(HEX[((code >> 8) & 0xF) as usize] as char);
buf.push(HEX[((code >> 4) & 0xF) as usize] as char);
buf.push(HEX[(code & 0xF) as usize] as char);
}

/// Escape an identifier for use as a property key.
fn escape_identifier(input: &Atom<'_>, escape_dollar: bool, always_quote: bool) -> String {
// Check if the identifier is a valid JavaScript identifier
Expand Down Expand Up @@ -1487,35 +1507,35 @@ mod tests {

#[test]
fn test_escape_string_unicode_literals() {
// Non-ASCII printable characters should be emitted as literal UTF-8,
// matching Angular's escapeIdentifier behavior.
// Non-ASCII characters should be escaped as \uNNNN to match
// TypeScript's emitter behavior.

// &times; (multiplication sign U+00D7) -> literal ×
assert_eq!(escape_string("\u{00D7}", false), "\"\u{00D7}\"");
// &times; (multiplication sign U+00D7) -> \u00D7
assert_eq!(escape_string("\u{00D7}", false), "\"\\u00D7\"");

// &nbsp; (non-breaking space U+00A0) -> literal
assert_eq!(escape_string("\u{00A0}", false), "\"\u{00A0}\"");
// &nbsp; (non-breaking space U+00A0) -> \u00A0
assert_eq!(escape_string("\u{00A0}", false), "\"\\u00A0\"");

// Mixed ASCII and non-ASCII
assert_eq!(escape_string("a\u{00D7}b", false), "\"a\u{00D7}b\"");
assert_eq!(escape_string("a\u{00D7}b", false), "\"a\\u00D7b\"");

// Multiple non-ASCII characters
assert_eq!(escape_string("\u{00D7}\u{00A0}", false), "\"\u{00D7}\u{00A0}\"");
assert_eq!(escape_string("\u{00D7}\u{00A0}", false), "\"\\u00D7\\u00A0\"");

// Characters outside BMP (emoji) -> emitted literally
assert_eq!(escape_string("\u{1F600}", false), "\"\u{1F600}\"");
// Characters outside BMP (emoji) -> surrogate pair
assert_eq!(escape_string("\u{1F600}", false), "\"\\uD83D\\uDE00\"");

// Common HTML entities -> all emitted literally
assert_eq!(escape_string("\u{00A9}", false), "\"\u{00A9}\""); // &copy; ©
assert_eq!(escape_string("\u{00AE}", false), "\"\u{00AE}\""); // &reg; ®
assert_eq!(escape_string("\u{2014}", false), "\"\u{2014}\""); // &mdash; —
assert_eq!(escape_string("\u{2013}", false), "\"\u{2013}\""); // &ndash; –
// Common HTML entities -> all escaped as \uNNNN
assert_eq!(escape_string("\u{00A9}", false), "\"\\u00A9\""); // &copy; ©
assert_eq!(escape_string("\u{00AE}", false), "\"\\u00AE\""); // &reg; ®
assert_eq!(escape_string("\u{2014}", false), "\"\\u2014\""); // &mdash; —
assert_eq!(escape_string("\u{2013}", false), "\"\\u2013\""); // &ndash; –

// Greek letter alpha
assert_eq!(escape_string("\u{03B1}", false), "\"\u{03B1}\""); // α
assert_eq!(escape_string("\u{03B1}", false), "\"\\u03B1\""); // α

// Accented Latin letter
assert_eq!(escape_string("\u{00E9}", false), "\"\u{00E9}\""); // é
assert_eq!(escape_string("\u{00E9}", false), "\"\\u00E9\""); // é
}

#[test]
Expand All @@ -1533,6 +1553,41 @@ mod tests {
assert_eq!(escape_string("\r", false), "\"\\r\"");
}

#[test]
fn test_escape_string_non_ascii_as_unicode_escapes() {
// Non-ASCII characters should be escaped as \uNNNN to match
// TypeScript's emitter behavior (which escapes non-ASCII in string literals).

// Non-breaking space U+00A0
assert_eq!(escape_string("\u{00A0}", false), "\"\\u00A0\"");

// En dash U+2013
assert_eq!(escape_string("\u{2013}", false), "\"\\u2013\"");

// Trademark U+2122
assert_eq!(escape_string("\u{2122}", false), "\"\\u2122\"");

// Infinity U+221E
assert_eq!(escape_string("\u{221E}", false), "\"\\u221E\"");

// Mixed ASCII and non-ASCII
assert_eq!(escape_string("a\u{00D7}b", false), "\"a\\u00D7b\"");

// Multiple non-ASCII characters
assert_eq!(escape_string("\u{00D7}\u{00A0}", false), "\"\\u00D7\\u00A0\"");

// Characters above BMP should use surrogate pairs
// U+1F600 (grinning face) = surrogate pair D83D DE00
assert_eq!(escape_string("\u{1F600}", false), "\"\\uD83D\\uDE00\"");

// U+10000 (first supplementary char) = surrogate pair D800 DC00
assert_eq!(escape_string("\u{10000}", false), "\"\\uD800\\uDC00\"");

// ASCII printable chars (0x20-0x7E) should remain literal
assert_eq!(escape_string(" ~", false), "\" ~\"");
assert_eq!(escape_string("abc123!@#", false), "\"abc123!@#\"");
}

// ========================================================================
// Source Map Tests
// ========================================================================
Expand Down
28 changes: 14 additions & 14 deletions crates/oxc_angular_compiler/tests/integration_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -145,26 +145,26 @@ fn test_multiple_interpolations() {

#[test]
fn test_html_entity_between_interpolations() {
// HTML entity &times; between two interpolations should produce literal UTF-8 in the output
// HTML entity &times; between two interpolations should produce \u00D7 in the output
let js = compile_template_to_js("<div>{{ a }}&times;{{ b }}</div>", "TestComponent");
// Should produce: textInterpolate2("", ctx.a, "\u{00D7}", ctx.b)
// Note: × (multiplication sign) = U+00D7, emitted as literal UTF-8
// Should produce: textInterpolate2("", ctx.a, "\u00D7", ctx.b)
// Note: × (multiplication sign) = U+00D7, escaped as \u00D7
assert!(
js.contains("textInterpolate2(\"\",ctx.a,\"\u{00D7}\",ctx.b)"),
"Expected textInterpolate2 with literal times character. Got:\n{js}"
js.contains(r#"textInterpolate2("",ctx.a,"\u00D7",ctx.b)"#),
"Expected textInterpolate2 with escaped times character. Got:\n{js}"
);
}

#[test]
fn test_html_entity_at_start_of_interpolation() {
// Entity at start: &times;{{ a }}
let js = compile_template_to_js("<div>&times;{{ a }}</div>", "TestComponent");
// Should produce: textInterpolate1("\u{00D7}", ctx.a)
// Note: × (multiplication sign) = U+00D7, emitted as literal UTF-8
// Should produce: textInterpolate1("\u00D7", ctx.a)
// Note: × (multiplication sign) = U+00D7, escaped as \u00D7
assert!(
js.contains("textInterpolate1(\"\u{00D7}\",ctx.a)")
|| js.contains("textInterpolate(\"\u{00D7}\",ctx.a)"),
"Expected textInterpolate with literal times character at start. Got:\n{js}"
js.contains(r#"textInterpolate1("\u00D7",ctx.a)"#)
|| js.contains(r#"textInterpolate("\u00D7",ctx.a)"#),
"Expected textInterpolate with escaped times character at start. Got:\n{js}"
);
}

Expand All @@ -173,11 +173,11 @@ fn test_multiple_html_entities_between_interpolations() {
// Multiple entities: {{ a }}&nbsp;&times;&nbsp;{{ b }}
let js =
compile_template_to_js("<div>{{ a }}&nbsp;&times;&nbsp;{{ b }}</div>", "TestComponent");
// Should produce: textInterpolate2("", ctx.a, "\u{00A0}\u{00D7}\u{00A0}", ctx.b)
// Note: &nbsp; = U+00A0, &times; = U+00D7, both emitted as literal UTF-8
// Should produce: textInterpolate2("", ctx.a, "\u00A0\u00D7\u00A0", ctx.b)
// Note: &nbsp; = U+00A0, &times; = U+00D7, both escaped as \uNNNN
assert!(
js.contains("textInterpolate2(\"\",ctx.a,\"\u{00A0}\u{00D7}\u{00A0}\",ctx.b)"),
"Expected textInterpolate2 with literal Unicode entities. Got:\n{js}"
js.contains(r#"textInterpolate2("",ctx.a,"\u00A0\u00D7\u00A0",ctx.b)"#),
"Expected textInterpolate2 with escaped Unicode entities. Got:\n{js}"
);
}

Expand Down
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