refactor(ecmascript): improve string to number conversion (#6577)

Author: magic-akari

crates/oxc_ecmascript/src/string_to_number.rs

@@ -2,8 +2,74 @@ pub trait StringToNumber {
     fn string_to_number(&self) -> f64;
 }
 
+/// `StringToNumber`
+///
+/// <https://tc39.es/ecma262/#sec-stringtonumber>
 impl StringToNumber for &str {
     fn string_to_number(&self) -> f64 {
-        self.parse::<f64>().unwrap_or(f64::NAN)
+        let s = self.trim_matches(is_trimmable_whitespace);
+
+        match s {
+            "" => return 0.0,
+            "-Infinity" => return f64::NEG_INFINITY,
+            "Infinity" | "+Infinity" => return f64::INFINITY,
+            // Make sure that no further variants of "infinity" are parsed.
+            "inf" | "-inf" | "+inf" => return f64::NAN,
+            _ => {}
+        }
+
+        let mut bytes = s.bytes();
+
+        if s.len() > 2 && bytes.next() == Some(b'0') {
+            let radix: u32 = match bytes.next() {
+                Some(b'x' | b'X') => 16,
+                Some(b'o' | b'O') => 8,
+                Some(b'b' | b'B') => 2,
+                _ => 0,
+            };
+
+            if radix != 0 {
+                let s = &s[2..];
+
+                // Fast path
+                if let Ok(value) = u32::from_str_radix(s, radix) {
+                    return f64::from(value);
+                }
+
+                // Slow path
+                let mut value: f64 = 0.0;
+                for c in bytes {
+                    if let Some(digit) = char::from(c).to_digit(radix) {
+                        value = value.mul_add(f64::from(radix), f64::from(digit));
+                    } else {
+                        return f64::NAN;
+                    }
+                }
+                return value;
+            }
+        }
+
+        s.parse::<f64>().unwrap_or(f64::NAN)
     }
 }
+
+// <https://github.com/boa-dev/boa/blob/94d08fe4e68791ceca3c4b7d94ccc5f3588feeb3/core/string/src/lib.rs#L55>
+/// Helper function to check if a `char` is trimmable.
+pub(crate) const fn is_trimmable_whitespace(c: char) -> bool {
+    // The rust implementation of `trim` does not regard the same characters whitespace as ecma standard does
+    //
+    // Rust uses \p{White_Space} by default, which also includes:
+    // `\u{0085}' (next line)
+    // And does not include:
+    // '\u{FEFF}' (zero width non-breaking space)
+    // Explicit whitespace: https://tc39.es/ecma262/#sec-white-space
+    matches!(
+        c,
+        '\u{0009}' | '\u{000B}' | '\u{000C}' | '\u{0020}' | '\u{00A0}' | '\u{FEFF}' |
+    // Unicode Space_Separator category
+    '\u{1680}' | '\u{2000}'
+            ..='\u{200A}' | '\u{202F}' | '\u{205F}' | '\u{3000}' |
+    // Line terminators: https://tc39.es/ecma262/#sec-line-terminators
+    '\u{000A}' | '\u{000D}' | '\u{2028}' | '\u{2029}'
+    )
+}