How to replace a Identifier node with a Literal node?

[rattlecattle]

I'm building a constant folding optimization pass. This is a contrived example of what I'm trying to achieve.

This is the orignal JS code.

const PI = 3.14;

function getPI() {
  return PI;
}

function area(r) {
  return PI * r * r;
}

I want to simplify it to the below.

function getPI() {
  return 3.14;
}

function area(r) {
  return 3.14 * r * r;
}

Using Scope and Bindings can already find out the places the variable PI is referenced. My question is how to replace occurences of the Identifier PI with the Literal 3.14 without implementing visit_xxx for VisitMut for every type of parent node the Identifier may be in?

For example,
In getPI, the parent of PI is ReturnStatement.
In area the parent is BinaryExpression.

Is there a way to avoid implemeting visit_xxx for each of ReturnStatement , BinaryExpression and so on to check if the child is an identifier and replace it with a Literal?

[overlookmotel]

PI is an IdentifierReference, which is a variant of Expression enum. So you can use VisitMut::visit_expression and replace that Expression with a different kind of Expression.

use oxc_ast::{
    ast::{Expression, NumberBase},
    visit::VisitMut,
    AstBuilder,
};

struct PiReplacer<'a> {
    ast_builder: AstBuilder<'a>,
}

impl<'a> VisitMut<'a> for PiReplacer<'a> {
    fn visit_expression(&mut self, expr: &mut Expression<'a>) {
        if let Expression::Identifier(ident) = expr {
            if ident.name == "PI" {
                *expr = self.ast_builder.expression_numeric_literal(
                    ident.span,
                    3.14,
                    None,
                    NumberBase::Decimal,
                );
            }
        }
    }
}