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

use crate::{
    exec::Executable,
    gc::{Finalize, Trace},
    syntax::ast::node::Node,
    value::{Type, Value},
    Context, Result,
};
use std::fmt;

#[cfg(feature = "deser")]
use serde::{Deserialize, Serialize};

/// This property accessor provides access to an object's properties by using the
/// [dot notation][mdn].
///
/// In the object.property syntax, the property must be a valid JavaScript identifier.
/// (In the ECMAScript standard, the names of properties are technically "IdentifierNames", not
/// "Identifiers", so reserved words can be used but are not recommended).
///
/// One can think of an object as an associative array (a.k.a. map, dictionary, hash, lookup
/// table). The keys in this array are the names of the object's properties.
///
/// It's typical when speaking of an object's properties to make a distinction between
/// properties and methods. However, the property/method distinction is little more than a
/// convention. A method is simply a property that can be called (for example, if it has a
/// reference to a Function instance as its value).
///
/// More information:
///  - [ECMAScript reference][spec]
///  - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#sec-property-accessors
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_accessors#Dot_notation
#[cfg_attr(feature = "deser", derive(Serialize, Deserialize))]
#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
pub struct GetConstField {
    obj: Box<Node>,
    field: Box<str>,
}

impl GetConstField {
    /// Creates a `GetConstField` AST node.
    pub fn new<V, L>(value: V, label: L) -> Self
    where
        V: Into<Node>,
        L: Into<Box<str>>,
    {
        Self {
            obj: Box::new(value.into()),
            field: label.into(),
        }
    }

    /// Gets the original object from where to get the field from.
    pub fn obj(&self) -> &Node {
        &self.obj
    }

    /// Gets the name of the field to retrieve.
    pub fn field(&self) -> &str {
        &self.field
    }
}

impl Executable for GetConstField {
    fn run(&self, context: &mut Context) -> Result<Value> {
        let mut obj = self.obj().run(context)?;
        if obj.get_type() != Type::Object {
            obj = Value::Object(obj.to_object(context)?);
        }

        Ok(obj.get_field(self.field(), context)?)
    }
}

impl fmt::Display for GetConstField {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}.{}", self.obj(), self.field())
    }
}

impl From<GetConstField> for Node {
    fn from(get_const_field: GetConstField) -> Self {
        Self::GetConstField(get_const_field)
    }
}