feat(es/react-compiler): Initialize support crate (#10422)

**Description:**

Currently, it only provides a way to check if a file is interesting target for the React Compiler

Author: kdy1

.changeset/eight-pens-relax.md

@@ -0,0 +1,6 @@
+---
+swc_core: minor
+swc_ecma_react_compiler: minor
+---
+
+feat(es/react-compiler): Initialize support crate

Cargo.lock

@@ -117,6 +117,9 @@ ecma_transforms_typescript = [
   "swc_ecma_transforms_typescript",
 ]
 
+ecma_react_compiler = ["swc_ecma_react_compiler"]
+
+
 # Enable swc_bundler
 bundler         = ["__bundler"]
 bundler_node_v1 = ["__bundler", "swc_node_bundler/swc_v1"]
@@ -373,6 +376,7 @@ swc_ecma_minifier                = { optional = true, version = "16.1.1", path =
 swc_ecma_parser                  = { optional = true, version = "11.1.4", path = "../swc_ecma_parser" }
 swc_ecma_preset_env              = { optional = true, version = "16.0.0", path = "../swc_ecma_preset_env" }
 swc_ecma_quote_macros            = { optional = true, version = "11.0.0", path = "../swc_ecma_quote_macros" }
+swc_ecma_react_compiler          = { optional = true, version = "1.0.0", path = "../swc_ecma_react_compiler" }
 swc_ecma_transforms_base         = { optional = true, version = "12.2.0", path = "../swc_ecma_transforms_base" }
 swc_ecma_transforms_compat       = { optional = true, version = "13.0.0", path = "../swc_ecma_transforms_compat" }
 swc_ecma_transforms_module       = { optional = true, version = "13.0.0", path = "../swc_ecma_transforms_module" }

crates/swc_core/Cargo.toml

@@ -154,6 +154,10 @@ pub mod ecma {
     pub mod utils {
         pub use swc_ecma_utils::*;
     }
+
+    #[cfg(feature = "swc_ecma_react_compiler")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "swc_ecma_react_compiler")))]
+    pub extern crate swc_ecma_react_compiler as react_compiler;
 }
 
 // swc features

crates/swc_core/src/lib.rs

@@ -0,0 +1,19 @@
+[package]
+description   = "SWC helpers for the React Compiler"
+documentation = "https://rustdoc.swc.rs/swc_ecma_react_compiler/"
+edition       = { workspace = true }
+license       = { workspace = true }
+name          = "swc_ecma_react_compiler"
+repository    = { workspace = true }
+version       = "1.0.0"
+
+
+    [package.metadata.docs.rs]
+    all-features = true
+    rustdoc-args = ["--cfg", "docsrs"]
+
+[dependencies]
+swc_atoms      = { version = "5.0.0", path = "../swc_atoms" }
+swc_common     = { version = "8.1.1", path = "../swc_common" }
+swc_ecma_ast   = { version = "8.1.2", path = "../swc_ecma_ast" }
+swc_ecma_visit = { version = "8.0.0", path = "../swc_ecma_visit" }

crates/swc_ecma_react_compiler/Cargo.toml

@@ -0,0 +1,73 @@
+use swc_ecma_ast::{Callee, Expr, FnDecl, FnExpr, Program, ReturnStmt};
+use swc_ecma_visit::{Visit, VisitWith};
+
+/// Returns true if the `program` is a good target for the react compiler.
+///
+/// If this function returns false, it means that it does not worth to apply the
+/// React Compiler to the file.
+pub fn is_required(program: &Program) -> bool {
+    let mut finder = Finder::default();
+    finder.visit_program(program);
+    finder.found
+}
+
+#[derive(Default)]
+struct Finder {
+    found: bool,
+
+    /// We are in a function that starts with a capital letter or it's a
+    /// function that starts with `use`
+    is_interested: bool,
+}
+
+impl Visit for Finder {
+    fn visit_callee(&mut self, node: &Callee) {
+        if self.is_interested {
+            if let Callee::Expr(e) = node {
+                if let Expr::Ident(c) = &**e {
+                    if c.sym.starts_with("use") {
+                        self.found = true;
+                        return;
+                    }
+                }
+            }
+        }
+
+        node.visit_children_with(self);
+    }
+
+    fn visit_fn_decl(&mut self, node: &FnDecl) {
+        let old = self.is_interested;
+        self.is_interested = node.ident.sym.starts_with("use")
+            || node.ident.sym.starts_with(|c: char| c.is_ascii_uppercase());
+
+        node.visit_children_with(self);
+
+        self.is_interested = old;
+    }
+
+    fn visit_fn_expr(&mut self, node: &FnExpr) {
+        let old = self.is_interested;
+
+        self.is_interested = node.ident.as_ref().is_some_and(|ident| {
+            ident.sym.starts_with("use") || ident.sym.starts_with(|c: char| c.is_ascii_uppercase())
+        });
+
+        node.visit_children_with(self);
+
+        self.is_interested = old;
+    }
+
+    fn visit_return_stmt(&mut self, node: &ReturnStmt) {
+        if self.is_interested {
+            if let Some(Expr::JSXElement(..) | Expr::JSXEmpty(..) | Expr::JSXFragment(..)) =
+                node.arg.as_deref()
+            {
+                self.found = true;
+                return;
+            }
+        }
+
+        node.visit_children_with(self);
+    }
+}

crates/swc_ecma_react_compiler/src/fast_check.rs

@@ -0,0 +1 @@
+pub mod fast_check;