refactor(transformer): use Option::get_or_insert_with (#6299)

`Option::get_or_insert_with` is designed for use case where you want to fill an `Option` if it's `None`, and get the contents either way. Use it in transformer where borrow checker allows.

crates/oxc_transformer/src/plugins/inject_global_variables.rs

@@ -236,13 +236,12 @@ impl<'a> InjectGlobalVariables<'a> {
                 if ReplaceGlobalDefines::is_dot_define(ctx.symbols(), dot_define, member) {
                     // If this is first replacement made for this dot define,
                     // create `Atom` for replacement, and record in `replaced_dot_defines`
-                    if value_atom.is_none() {
-                        *value_atom = Some(self.ast.atom(dot_define.value.as_str()));
-
+                    let value_atom = value_atom.get_or_insert_with(|| {
                         self.replaced_dot_defines
                             .push((dot_define.parts[0].clone(), dot_define.value.clone()));
-                    }
-                    let value_atom = value_atom.as_ref().unwrap().clone();
+                        self.ast.atom(dot_define.value.as_str())
+                    });
+                    let value_atom = value_atom.clone();
 
                     let value = self.ast.expression_identifier_reference(SPAN, value_atom);
                     *expr = value;

crates/oxc_transformer/src/react/jsx_source.rs

@@ -77,10 +77,9 @@ impl<'a, 'ctx> Traverse<'a> for ReactJsxSource<'a, 'ctx> {
 
 impl<'a, 'ctx> ReactJsxSource<'a, 'ctx> {
     pub fn get_line_column(&mut self, offset: u32) -> (usize, usize) {
-        if self.source_rope.is_none() {
-            self.source_rope = Some(Rope::from_str(self.ctx.source_text));
-        }
-        get_line_column(self.source_rope.as_ref().unwrap(), offset, self.ctx.source_text)
+        let source_rope =
+            self.source_rope.get_or_insert_with(|| Rope::from_str(self.ctx.source_text));
+        get_line_column(source_rope, offset, self.ctx.source_text)
     }
 
     pub fn get_object_property_kind_for_jsx_plugin(
@@ -221,11 +220,8 @@ impl<'a, 'ctx> ReactJsxSource<'a, 'ctx> {
     }
 
     fn get_filename_var(&mut self, ctx: &mut TraverseCtx<'a>) -> &BoundIdentifier<'a> {
-        if self.filename_var.is_none() {
-            self.filename_var = Some(
-                ctx.generate_uid_in_root_scope(FILE_NAME_VAR, SymbolFlags::FunctionScopedVariable),
-            );
-        }
-        self.filename_var.as_ref().unwrap()
+        self.filename_var.get_or_insert_with(|| {
+            ctx.generate_uid_in_root_scope(FILE_NAME_VAR, SymbolFlags::FunctionScopedVariable)
+        })
     }
 }