fix(formatjs): Variable evaluate concatenation

[cuyl]

A huge refactor to improve variable evaluate for defaultMessage and description.

Fixes #564, Fixes #565, Fixes #566

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[kdy1]

See https://rustdoc.swc.rs/swc_ecma_minifier/eval/struct.Evaluator.html
Please use it, instead of implemengint it manually.

[cuyl]

@kdy1 Thanks

[cuyl]

I’ve attempted to refactor the evaluation logic by replacing evaluate_template_literal_string_with_visitor with Evaluator::eval_tpl and evaluate_expression_with_visitor with Evaluator::eval.

However, it appears that Evaluator::eval does not currently support BinaryExpression, which is causing the current build/test failures.

So I leave evaluate_expression_with_visitor here, and I found some code in crates/swc_ecma_minifier/src/compress/pure/strings.rs can concat strings but it's private that I cannot use.

@kdy1

[kdy1]

Can you send a PR towards https://github.com/swc-project/swc?

[kdy1]

You can patch your crates locally using https://github.com/swc-project/swc/blob/main/scripts/cargo/patch-section.sh

See: https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html

[cuyl]

OK, I will open a PR to swc.
@kdy1

[cuyl]

Waiting for swc-project/swc#11390

I found that Evaluator::data does similar job with variable_bindings here, so I move the resolve_identifier to Evaluator.
In order to keep React Compiler work #467 , I have to explode the store function.
I'm not sure if we can move this part of logic to swc.

plugins/packages/formatjs/transform/src/lib.rs

Lines 945 to 974 in 947ff3f

	fn visit_mut_assign_expr(&mut self, assign_expr: &mut AssignExpr) {
	assign_expr.visit_mut_children_with(self);
	// Track assignment expressions for React Compiler optimizations
	// Handle patterns like: t1 = { ... }
	if let AssignTarget::Simple(SimpleAssignTarget::Ident(ident)) = &assign_expr.left {
	let variable_id = ident.id.to_id();
	// Check if we already have a binding for this variable
	let should_update = match self.resolve_identifier(ident) {
	Some(existing_expr) => {
	// Only overwrite if the new expression is an object literal
	// and the existing one is not, or if both are object literals
	match (existing_expr, &*assign_expr.right) {
	(Expr::Object(_), Expr::Object(_)) => true, // Both objects, update
	(_, Expr::Object(_)) => true, /* New is object, existing */
	// is not, update
	(Expr::Object(_), _) => false, /* Existing is object, new is not, don't */
	// update
	_ => true, // Neither is object, update
	}
	}
	None => true, // No existing binding, always update
	};
	if should_update {
	self.evaluator.store(variable_id, &assign_expr.right);
	}
	}
	}

@kdy1

[kdy1]

I think we should move it to the main SWC repository. Nice catch! It seems like I didn't review the PR for fixing the React Compielr support carefully enough.

[kdy1]

Do you want me to update swc_core of this repository to reflect Evaluator changes?

[kdy1]

Oh… I realized that I forgot to publish the changes. My bad, sorry.

[cuyl]

No worries, you can publish it and then upgrade swc_core in this branch.
@kdy1