mirror of
https://github.com/danbulant/oxc
synced 2026-05-25 12:51:57 +00:00
34 lines
1,008 B
Rust
34 lines
1,008 B
Rust
use crate::ToInt32;
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pub trait StringCharAt {
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/// `String.prototype.charAt ( pos )`
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/// <https://tc39.es/ecma262/#sec-string.prototype.charat>
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fn char_at(&self, index: Option<f64>) -> Option<char>;
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}
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impl StringCharAt for &str {
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#[expect(clippy::cast_sign_loss)]
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fn char_at(&self, index: Option<f64>) -> Option<char> {
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let index = index.map_or(0, |x| x.to_int_32() as isize);
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if index < 0 {
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None
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} else {
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self.chars().nth(index as usize)
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}
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}
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}
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#[cfg(test)]
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mod test {
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#[test]
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fn test_evaluate_string_char_at() {
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use crate::string_char_at::StringCharAt;
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assert_eq!("test".char_at(Some(0.0)), Some('t'));
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assert_eq!("test".char_at(Some(1.0)), Some('e'));
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assert_eq!("test".char_at(Some(2.0)), Some('s'));
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assert_eq!("test".char_at(Some(-1.0)), None);
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assert_eq!("test".char_at(Some(-1.1)), None);
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assert_eq!("test".char_at(Some(-1_073_741_825.0)), None);
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}
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}
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