LibJS: Add spec comments to bitwise_and()

1 files changed, 19 insertions, 1 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/Value.cpp b/Userland/Libraries/LibJS/Runtime/Value.cpp
index 37b6a045f5..b1b3b2b15f 100644
--- a/Userland/Libraries/LibJS/Runtime/Value.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Value.cpp
@@ -1305,17 +1305,35 @@ ThrowCompletionOr<Value> less_than_equals(VM& vm, Value lhs, Value rhs)
 }
 
 // 13.12 Binary Bitwise Operators, https://tc39.es/ecma262/#sec-binary-bitwise-operators
+// BitwiseANDExpression : BitwiseANDExpression & EqualityExpression
 ThrowCompletionOr<Value> bitwise_and(VM& vm, Value lhs, Value rhs)
 {
+    // 13.15.3 ApplyStringOrNumericBinaryOperator ( lval, opText, rval ), https://tc39.es/ecma262/#sec-applystringornumericbinaryoperator
+    // 1-2, 6. N/A.
+
+    // 3. Let lnum be ? ToNumeric(lval).
     auto lhs_numeric = TRY(lhs.to_numeric(vm));
+
+    // 4. Let rnum be ? ToNumeric(rval).
     auto rhs_numeric = TRY(rhs.to_numeric(vm));
+
+    // 7. Let operation be the abstract operation associated with opText and Type(lnum) in the following table:
+    // [...]
+    // 8. Return operation(lnum, rnum).
     if (both_number(lhs_numeric, rhs_numeric)) {
+        // 6.1.6.1.17 Number::bitwiseAND ( x, y ), https://tc39.es/ecma262/#sec-numeric-types-number-bitwiseAND
+        // 1. Return NumberBitwiseOp(&, x, y).
         if (!lhs_numeric.is_finite_number() || !rhs_numeric.is_finite_number())
             return Value(0);
         return Value(TRY(lhs_numeric.to_i32(vm)) & TRY(rhs_numeric.to_i32(vm)));
     }
-    if (both_bigint(lhs_numeric, rhs_numeric))
+    if (both_bigint(lhs_numeric, rhs_numeric)) {
+        // 6.1.6.2.18 BigInt::bitwiseAND ( x, y ), https://tc39.es/ecma262/#sec-numeric-types-bigint-bitwiseAND
+        // 1. Return BigIntBitwiseOp(&, x, y).
         return BigInt::create(vm, lhs_numeric.as_bigint().big_integer().bitwise_and(rhs_numeric.as_bigint().big_integer()));
+    }
+
+    // 5. If Type(lnum) is different from Type(rnum), throw a TypeError exception.
     return vm.throw_completion<TypeError>(ErrorType::BigIntBadOperatorOtherType, "bitwise AND");
 }