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use crate::{
builtins::{function::make_builtin_fn, iterable::create_iter_result_object, Array, Value},
gc::{Finalize, Trace},
object::{GcObject, ObjectData},
property::{Attribute, DataDescriptor},
BoaProfiler, Context, Result,
};
#[derive(Debug, Clone, Finalize, Trace)]
pub enum ArrayIterationKind {
Key,
Value,
KeyAndValue,
}
#[derive(Debug, Clone, Finalize, Trace)]
pub struct ArrayIterator {
array: Value,
next_index: u32,
kind: ArrayIterationKind,
}
impl ArrayIterator {
pub(crate) const NAME: &'static str = "ArrayIterator";
fn new(array: Value, kind: ArrayIterationKind) -> Self {
ArrayIterator {
array,
kind,
next_index: 0,
}
}
pub(crate) fn create_array_iterator(
context: &Context,
array: Value,
kind: ArrayIterationKind,
) -> Result<Value> {
let array_iterator = Value::new_object(context);
array_iterator.set_data(ObjectData::ArrayIterator(Self::new(array, kind)));
array_iterator
.as_object()
.expect("array iterator object")
.set_prototype_instance(context.iterator_prototypes().array_iterator().into());
Ok(array_iterator)
}
pub(crate) fn next(this: &Value, _: &[Value], context: &mut Context) -> Result<Value> {
if let Value::Object(ref object) = this {
let mut object = object.borrow_mut();
if let Some(array_iterator) = object.as_array_iterator_mut() {
let index = array_iterator.next_index;
if array_iterator.array.is_undefined() {
return Ok(create_iter_result_object(context, Value::undefined(), true));
}
let len = array_iterator
.array
.get_field("length", context)?
.as_number()
.ok_or_else(|| context.construct_type_error("Not an array"))?
as u32;
if array_iterator.next_index >= len {
array_iterator.array = Value::undefined();
return Ok(create_iter_result_object(context, Value::undefined(), true));
}
array_iterator.next_index = index + 1;
match array_iterator.kind {
ArrayIterationKind::Key => {
Ok(create_iter_result_object(context, index.into(), false))
}
ArrayIterationKind::Value => {
let element_value = array_iterator.array.get_field(index, context)?;
Ok(create_iter_result_object(context, element_value, false))
}
ArrayIterationKind::KeyAndValue => {
let element_value = array_iterator.array.get_field(index, context)?;
let result = Array::constructor(
&Value::new_object(context),
&[index.into(), element_value],
context,
)?;
Ok(create_iter_result_object(context, result, false))
}
}
} else {
context.throw_type_error("`this` is not an ArrayIterator")
}
} else {
context.throw_type_error("`this` is not an ArrayIterator")
}
}
pub(crate) fn create_prototype(context: &mut Context, iterator_prototype: Value) -> GcObject {
let _timer = BoaProfiler::global().start_event(Self::NAME, "init");
let mut array_iterator = context.construct_object();
make_builtin_fn(Self::next, "next", &array_iterator, 0, context);
array_iterator.set_prototype_instance(iterator_prototype);
let to_string_tag = context.well_known_symbols().to_string_tag_symbol();
let to_string_tag_property = DataDescriptor::new("Array Iterator", Attribute::CONFIGURABLE);
array_iterator.insert(to_string_tag, to_string_tag_property);
array_iterator
}
}