pipa-js 0.1.3

A fast, minimal ES2023 JavaScript runtime built in Rust.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

use std::fmt;

#[derive(Debug, Clone, Default)]
pub struct SourceLocation {
    pub filename: String,
    pub line: u32,
    pub column: u32,
}

impl SourceLocation {
    pub fn new(filename: impl Into<String>, line: u32, column: u32) -> Self {
        Self {
            filename: filename.into(),
            line,
            column,
        }
    }

    pub fn unknown() -> Self {
        Self {
            filename: "<anonymous>".to_string(),
            line: 0,
            column: 0,
        }
    }
}

impl fmt::Display for SourceLocation {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}:{}:{}", self.filename, self.line, self.column)
    }
}

pub type LineNumberEntry = (u32, u32);

#[derive(Debug, Clone, Default)]
pub struct LineNumberTable {
    entries: Vec<LineNumberEntry>,
}

impl LineNumberTable {
    pub fn new() -> Self {
        Self {
            entries: Vec::new(),
        }
    }

    pub fn add_entry(&mut self, instruction_offset: u32, line_number: u32) {
        if let Some(pos) = self
            .entries
            .binary_search_by(|(off, _)| off.cmp(&instruction_offset))
            .ok()
        {
            self.entries[pos] = (instruction_offset, line_number);
        } else {
            let pos = self
                .entries
                .partition_point(|(off, _)| *off < instruction_offset);
            self.entries.insert(pos, (instruction_offset, line_number));
        }
    }

    pub fn lookup_line(&self, instruction_offset: u32) -> Option<u32> {
        match self
            .entries
            .binary_search_by(|(off, _)| off.cmp(&instruction_offset))
        {
            Ok(idx) => Some(self.entries[idx].1),
            Err(idx) if idx > 0 => Some(self.entries[idx - 1].1),
            _ => None,
        }
    }

    pub fn entries(&self) -> &[LineNumberEntry] {
        &self.entries
    }
}

#[derive(Debug, Clone)]
pub struct FrameInfo {
    pub function_name: String,
    pub location: SourceLocation,
}

impl FrameInfo {
    pub fn new(function_name: impl Into<String>, location: SourceLocation) -> Self {
        Self {
            function_name: function_name.into(),
            location,
        }
    }
}

pub struct TracebackFormatter;

impl TracebackFormatter {
    pub fn format(error_message: &str, frames: &[FrameInfo], error_type: Option<&str>) -> String {
        let mut result = String::new();

        if let Some(etype) = error_type {
            result.push_str(&format!("Uncaught {}: {}", etype, error_message));
        } else {
            result.push_str(&format!("Uncaught: {}", error_message));
        }
        result.push('\n');

        for frame in frames.iter().rev() {
            result.push_str(&format!(
                "    at {} ({}:{}:{})\n",
                frame.function_name,
                frame.location.filename,
                frame.location.line,
                frame.location.column
            ));
        }

        result
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_line_number_table() {
        let mut table = LineNumberTable::new();

        table.add_entry(0, 1);
        table.add_entry(10, 2);
        table.add_entry(25, 5);

        assert_eq!(table.lookup_line(0), Some(1));
        assert_eq!(table.lookup_line(5), Some(1));
        assert_eq!(table.lookup_line(10), Some(2));
        assert_eq!(table.lookup_line(20), Some(2));
        assert_eq!(table.lookup_line(25), Some(5));
        assert_eq!(table.lookup_line(100), Some(5));
    }

    #[test]
    fn test_traceback_formatter() {
        let frames = vec![
            FrameInfo::new("inner", SourceLocation::new("test.js", 3, 5)),
            FrameInfo::new("outer", SourceLocation::new("test.js", 7, 2)),
            FrameInfo::new("global", SourceLocation::new("test.js", 10, 1)),
        ];

        let output = TracebackFormatter::format("x is not a function", &frames, Some("TypeError"));

        assert!(output.contains("Uncaught TypeError: x is not a function"));
        assert!(output.contains("at inner (test.js:3:5)"));
        assert!(output.contains("at outer (test.js:7:2)"));
        assert!(output.contains("at global (test.js:10:1)"));
    }
}