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use swc_common::{util::take::Take, DUMMY_SP};
use swc_ecma_ast::*;
use swc_ecma_utils::alias_ident_for;
use crate::CompilerImpl;
impl<'a> CompilerImpl<'a> {
/// Memorize computed property name for logical assignments
pub(super) fn memorize_prop_for_logical_assignment(
&mut self,
c: ComputedPropName,
) -> (ComputedPropName, ComputedPropName) {
let alias = alias_ident_for(&c.expr, "_ref");
self.es2021_logical_assignment_vars.push(VarDeclarator {
span: DUMMY_SP,
name: alias.clone().into(),
init: None,
definite: false,
});
(
ComputedPropName {
span: c.span,
expr: AssignExpr {
span: DUMMY_SP,
left: alias.clone().into(),
op: op!("="),
right: c.expr,
}
.into(),
},
ComputedPropName {
span: c.span,
expr: Box::new(alias.into()),
},
)
}
/// Transform logical assignment operators (&&=, ||=, ??=) to binary
/// expressions
pub(crate) fn transform_logical_assignment(&mut self, e: &mut Expr) -> bool {
if let Expr::Assign(AssignExpr {
span,
op: op @ (op!("&&=") | op!("||=") | op!("??=")),
left: AssignTarget::Simple(left),
right,
}) = e
{
let (left_expr, r_assign_target) = match &mut *left {
SimpleAssignTarget::SuperProp(SuperPropExpr {
span,
obj,
prop: SuperProp::Computed(c),
}) => {
let (left, right) = self.memorize_prop_for_logical_assignment(c.take());
(
Box::new(
SuperPropExpr {
span: *span,
obj: *obj,
prop: SuperProp::Computed(left),
}
.into(),
),
Box::new(
SuperPropExpr {
span: *span,
obj: *obj,
prop: SuperProp::Computed(right),
}
.into(),
),
)
}
SimpleAssignTarget::Member(m) => {
let (left_obj, right_obj) = match *m.obj.take() {
// TODO: local vars
obj @ Expr::This(_) => (obj.clone().into(), obj.into()),
obj => {
let alias = alias_ident_for(&obj, "_ref");
self.es2021_logical_assignment_vars.push(VarDeclarator {
span: DUMMY_SP,
name: alias.clone().into(),
init: None,
definite: false,
});
(
AssignExpr {
span: DUMMY_SP,
op: op!("="),
left: alias.clone().into(),
right: obj.into(),
}
.into(),
alias.into(),
)
}
};
let (left_prop, right_prop) = match m.prop.take() {
MemberProp::Computed(c) => {
let (left, right) = self.memorize_prop_for_logical_assignment(c);
(left.into(), right.into())
}
prop => (prop.clone(), prop),
};
(
MemberExpr {
span: DUMMY_SP,
obj: left_obj,
prop: left_prop,
}
.into(),
MemberExpr {
span: DUMMY_SP,
obj: right_obj,
prop: right_prop,
}
.into(),
)
}
_ => {
let expr: Box<Expr> = left.take().into();
(expr.clone(), expr)
}
};
let right = AssignExpr {
span: DUMMY_SP,
op: op!("="),
left: r_assign_target.try_into().unwrap(),
right: right.take(),
}
.into();
let op = match *op {
op!("??=") => op!("??"),
op!("&&=") => op!("&&"),
op!("||=") => op!("||"),
_ => unreachable!(),
};
*e = BinExpr {
span: *span,
op,
left: left_expr,
right,
}
.into();
return true;
}
false
}
}