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use super::{JsBigInt, JsObject, JsResult, JsValue, PreferredType};
use crate::{builtins::Number, Context};
impl JsValue {
/// Strict equality comparison.
///
/// This method is executed when doing strict equality comparisons with the `===` operator.
/// For more information, check <https://tc39.es/ecma262/#sec-strict-equality-comparison>.
pub fn strict_equals(&self, other: &Self) -> bool {
// 1. If Type(x) is different from Type(y), return false.
if self.get_type() != other.get_type() {
return false;
}
match (self, other) {
// 2. If Type(x) is Number or BigInt, then
// a. Return ! Type(x)::equal(x, y).
(Self::BigInt(x), Self::BigInt(y)) => JsBigInt::equal(x, y),
(Self::Rational(x), Self::Rational(y)) => Number::equal(*x, *y),
(Self::Rational(x), Self::Integer(y)) => Number::equal(*x, f64::from(*y)),
(Self::Integer(x), Self::Rational(y)) => Number::equal(f64::from(*x), *y),
(Self::Integer(x), Self::Integer(y)) => x == y,
//Null has to be handled specially because "typeof null" returns object and if we managed
//this without a special case we would compare self and other as if they were actually
//objects which unfortunately fails
//Specification Link: https://tc39.es/ecma262/#sec-typeof-operator
(Self::Null, Self::Null) => true,
// 3. Return ! SameValueNonNumeric(x, y).
(_, _) => Self::same_value_non_numeric(self, other),
}
}
/// Abstract equality comparison.
///
/// This method is executed when doing abstract equality comparisons with the `==` operator.
/// For more information, check <https://tc39.es/ecma262/#sec-abstract-equality-comparison>
#[allow(clippy::float_cmp)]
pub fn equals(&self, other: &Self, context: &mut Context<'_>) -> JsResult<bool> {
// 1. If Type(x) is the same as Type(y), then
// a. Return the result of performing Strict Equality Comparison x === y.
if self.get_type() == other.get_type() {
return Ok(self.strict_equals(other));
}
Ok(match (self, other) {
// 2. If x is null and y is undefined, return true.
// 3. If x is undefined and y is null, return true.
(Self::Null, Self::Undefined) | (Self::Undefined, Self::Null) => true,
// 3. If Type(x) is Number and Type(y) is String, return the result of the comparison x == ! ToNumber(y).
// 4. If Type(x) is String and Type(y) is Number, return the result of the comparison ! ToNumber(x) == y.
//
// https://github.com/rust-lang/rust/issues/54883
(Self::Integer(_) | Self::Rational(_), Self::String(_) | Self::Boolean(_))
| (Self::String(_), Self::Integer(_) | Self::Rational(_)) => {
let x = self.to_number(context)?;
let y = other.to_number(context)?;
Number::equal(x, y)
}
// 6. If Type(x) is BigInt and Type(y) is String, then
// a. Let n be ! StringToBigInt(y).
// b. If n is NaN, return false.
// c. Return the result of the comparison x == n.
(Self::BigInt(ref a), Self::String(ref b)) => {
b.to_big_int().as_ref().map_or(false, |b| a == b)
}
// 7. If Type(x) is String and Type(y) is BigInt, return the result of the comparison y == x.
(Self::String(ref a), Self::BigInt(ref b)) => {
a.to_big_int().as_ref().map_or(false, |a| a == b)
}
// 8. If Type(x) is Boolean, return the result of the comparison ! ToNumber(x) == y.
(Self::Boolean(x), _) => return other.equals(&Self::new(i32::from(*x)), context),
// 9. If Type(y) is Boolean, return the result of the comparison x == ! ToNumber(y).
(_, Self::Boolean(y)) => return self.equals(&Self::new(i32::from(*y)), context),
// 10. If Type(x) is either String, Number, BigInt, or Symbol and Type(y) is Object, return the result
// of the comparison x == ? ToPrimitive(y).
(
Self::Object(_),
Self::String(_)
| Self::Rational(_)
| Self::Integer(_)
| Self::BigInt(_)
| Self::Symbol(_),
) => {
let primitive = self.to_primitive(context, PreferredType::Default)?;
return Ok(primitive
.equals(other, context)
.expect("should not fail according to spec"));
}
// 11. If Type(x) is Object and Type(y) is either String, Number, BigInt, or Symbol, return the result
// of the comparison ? ToPrimitive(x) == y.
(
Self::String(_)
| Self::Rational(_)
| Self::Integer(_)
| Self::BigInt(_)
| Self::Symbol(_),
Self::Object(_),
) => {
let primitive = other.to_primitive(context, PreferredType::Default)?;
return Ok(primitive
.equals(self, context)
.expect("should not fail according to spec"));
}
// 12. If Type(x) is BigInt and Type(y) is Number, or if Type(x) is Number and Type(y) is BigInt, then
// a. If x or y are any of NaN, +∞, or -∞, return false.
// b. If the mathematical value of x is equal to the mathematical value of y, return true; otherwise return false.
(Self::BigInt(ref a), Self::Rational(ref b)) => a == b,
(Self::Rational(ref a), Self::BigInt(ref b)) => a == b,
(Self::BigInt(ref a), Self::Integer(ref b)) => a == b,
(Self::Integer(ref a), Self::BigInt(ref b)) => a == b,
// 13. Return false.
_ => false,
})
}
/// The internal comparison abstract operation SameValue(x, y),
/// where x and y are ECMAScript language values, produces true or false.
///
/// More information:
/// - [ECMAScript][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-samevalue
pub fn same_value(x: &Self, y: &Self) -> bool {
// 1. If Type(x) is different from Type(y), return false.
if x.get_type() != y.get_type() {
return false;
}
match (x, y) {
// 2. If Type(x) is Number or BigInt, then
// a. Return ! Type(x)::SameValue(x, y).
(Self::BigInt(x), Self::BigInt(y)) => JsBigInt::same_value(x, y),
(Self::Rational(x), Self::Rational(y)) => Number::same_value(*x, *y),
(Self::Rational(x), Self::Integer(y)) => Number::same_value(*x, f64::from(*y)),
(Self::Integer(x), Self::Rational(y)) => Number::same_value(f64::from(*x), *y),
(Self::Integer(x), Self::Integer(y)) => x == y,
// 3. Return ! SameValueNonNumeric(x, y).
(_, _) => Self::same_value_non_numeric(x, y),
}
}
/// The internal comparison abstract operation `SameValueZero(x, y)`,
/// where `x` and `y` are ECMAScript language values, produces `true` or `false`.
///
/// `SameValueZero` differs from `SameValue` only in its treatment of `+0` and `-0`.
///
/// More information:
/// - [ECMAScript][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-samevaluezero
pub fn same_value_zero(x: &Self, y: &Self) -> bool {
if x.get_type() != y.get_type() {
return false;
}
match (x, y) {
// 2. If Type(x) is Number or BigInt, then
// a. Return ! Type(x)::SameValueZero(x, y).
(Self::BigInt(x), Self::BigInt(y)) => JsBigInt::same_value_zero(x, y),
(Self::Rational(x), Self::Rational(y)) => Number::same_value_zero(*x, *y),
(Self::Rational(x), Self::Integer(y)) => Number::same_value_zero(*x, f64::from(*y)),
(Self::Integer(x), Self::Rational(y)) => Number::same_value_zero(f64::from(*x), *y),
(Self::Integer(x), Self::Integer(y)) => x == y,
// 3. Return ! SameValueNonNumeric(x, y).
(_, _) => Self::same_value_non_numeric(x, y),
}
}
fn same_value_non_numeric(x: &Self, y: &Self) -> bool {
debug_assert!(x.get_type() == y.get_type());
match (x, y) {
(Self::Null, Self::Null) | (Self::Undefined, Self::Undefined) => true,
(Self::String(ref x), Self::String(ref y)) => x == y,
(Self::Boolean(x), Self::Boolean(y)) => x == y,
(Self::Object(ref x), Self::Object(ref y)) => JsObject::equals(x, y),
(Self::Symbol(ref x), Self::Symbol(ref y)) => x == y,
_ => false,
}
}
}