feat(bindings/ts): Add transform/strip-only mode (#9138)

**Description:**

This PR adds `strip-only`/`transform` mode to `@swc/wasm-typescript`.

 - Both mode errors on decorator usages.
 - In `strip-only` mode, `enum` and TypeScript parameter properties are treated as an invalid syntax.
 - In `transform` mode, those are transpiled.

bindings/binding_typescript_wasm/Cargo.toml

@@ -13,9 +13,6 @@ bench      = false
 crate-type = ["cdylib"]
 
 [features]
-default = ["swc_v1"]
-swc_v1  = []
-swc_v2  = []
 
 [dependencies]
 anyhow = "1.0.66"

bindings/binding_typescript_wasm/__tests__/__snapshots__/transform.js.snap

@@ -0,0 +1,32 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`transform in strip-only mode should throw an error when it encounters an enum 1`] = `
+"
+  x TypeScript enum is not supported in strip-only mode
+   ,----
+ 1 | enum Foo {}
+   : ^^^^^^^^^^^
+   \`----
+"
+`;
+
+exports[`transform in strip-only mode should throw an error with a descriptive message when it encounters a decorator 1`] = `
+"
+  x Decorators are not supported
+   ,----
+ 1 | class Foo { @decorator foo() {} }
+   :             ^^^^^^^^^^
+   \`----
+"
+`;
+
+exports[`transform in transform mode should transpile enum 1`] = `
+"var Foo;
+(function(Foo) {})(Foo || (Foo = {}));
+"
+`;
+
+exports[`transform should strip types 1`] = `
+"export const foo = 1;
+"
+`;

bindings/binding_typescript_wasm/__tests__/transform.js

@@ -6,7 +6,7 @@ it("properly reports error", function () {
     }).toThrow();
 });
 
-describe("trannsform", () => {
+describe("transform", () => {
     it("should strip types", async () => {
         const { code } = await swc.transform(
             `
@@ -15,26 +15,36 @@ describe("trannsform", () => {
     `,
             {}
         );
-        expect(code).toMatchInlineSnapshot(`
-            "export const foo = 1;
-            "
-        `);
+        expect(code).toMatchSnapshot();
     });
 
-    it("should preserve enum", async () => {
-        const { code } = await swc.transform(
-            `
-            enum Foo {
-                Bar
-            }
-                `,
-            {}
-        );
-        await expect(code).toMatchInlineSnapshot(`
-            "enum Foo {
-                Bar
-            }
-            "
-        `);
+    describe("in strip-only mode", () => {
+        it("should throw an error when it encounters an enum", async () => {
+            await expect(
+                swc.transform("enum Foo {}", {
+                    mode: "strip-only",
+                })
+            ).rejects.toMatchSnapshot();
+        });
+
+        it('should throw an error with a descriptive message when it encounters a decorator', async () => {
+            await expect(
+                swc.transform("class Foo { @decorator foo() {} }", {
+                    mode: "strip-only",
+                })
+            ).rejects.toMatchSnapshot();
+        })
+    });
+
+    describe("in transform mode", () => {
+        it("should transpile enum", async () => {
+            const { code } = await swc.transform("enum Foo {}", {
+                mode: "transform",
+            });
+
+            expect(code).toMatchSnapshot();
+        });
+
+
     });
 });

bindings/binding_typescript_wasm/package.json

@@ -1,5 +1,5 @@
 {
     "devDependencies": {
-        "jest": "^25.1.0"
+        "jest": "^29.7.0"
     }
 }

bindings/binding_typescript_wasm/src/lib.rs

@@ -2,11 +2,14 @@ use anyhow::{Context, Error};
 use serde::{Deserialize, Serialize};
 use swc_core::{
     common::{
-        comments::SingleThreadedComments, errors::ColorConfig, source_map::SourceMapGenConfig,
-        sync::Lrc, FileName, Mark, SourceMap, GLOBALS,
+        comments::SingleThreadedComments,
+        errors::{ColorConfig, HANDLER},
+        source_map::SourceMapGenConfig,
+        sync::Lrc,
+        FileName, Mark, SourceMap, Spanned, GLOBALS,
     },
     ecma::{
-        ast::{EsVersion, Program},
+        ast::{Decorator, EsVersion, Program, TsEnumDecl, TsParamPropParam},
         codegen::text_writer::JsWriter,
         parser::{
             parse_file_as_module, parse_file_as_program, parse_file_as_script, Syntax, TsSyntax,
@@ -18,9 +21,9 @@ use swc_core::{
                 hygiene::hygiene,
                 resolver,
             },
-            typescript::strip_type,
+            typescript::{strip_type, typescript},
         },
-        visit::VisitMutWith,
+        visit::{Visit, VisitMutWith, VisitWith},
     },
 };
 use swc_error_reporters::handler::{try_with_handler, HandlerOpts};
@@ -46,7 +49,7 @@ pub struct Options {
     #[serde(default)]
     pub filename: Option<String>,
 
-    #[serde(default)]
+    #[serde(default = "default_ts_syntax")]
     pub parser: TsSyntax,
 
     #[serde(default)]
@@ -55,12 +58,31 @@ pub struct Options {
     #[serde(default)]
     pub source_maps: bool,
 
-    // #[serde(default)]
-    // pub transform: swc_core::ecma::transforms::typescript::Config,
+    #[serde(default)]
+    pub mode: Mode,
+
+    #[serde(default)]
+    pub transform: Option<swc_core::ecma::transforms::typescript::Config>,
+
     #[serde(default)]
     pub codegen: swc_core::ecma::codegen::Config,
 }
 
+fn default_ts_syntax() -> TsSyntax {
+    TsSyntax {
+        decorators: true,
+        ..Default::default()
+    }
+}
+
+#[derive(Clone, Copy, Default, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+pub enum Mode {
+    #[default]
+    StripOnly,
+    Transform,
+}
+
 #[derive(Serialize)]
 pub struct TransformOutput {
     code: String,
@@ -142,15 +164,26 @@ fn operate(input: String, options: Options) -> Result<TransformOutput, Error> {
 
             let unresolved_mark = Mark::new();
             let top_level_mark = Mark::new();
-
             HELPERS.set(&Helpers::new(options.external_helpers), || {
                 // Apply resolver
 
                 program.visit_mut_with(&mut resolver(unresolved_mark, top_level_mark, true));
 
                 // Strip typescript types
 
-                program.visit_mut_with(&mut strip_type());
+                program.visit_with(&mut Validator { mode: options.mode });
+
+                match options.mode {
+                    Mode::StripOnly => {
+                        program.visit_mut_with(&mut strip_type());
+                    }
+                    Mode::Transform => {
+                        program.visit_mut_with(&mut typescript(
+                            options.transform.unwrap_or_default(),
+                            top_level_mark,
+                        ));
+                    }
+                }
 
                 // Apply external helpers
 
@@ -217,3 +250,43 @@ impl SourceMapGenConfig for TsSourceMapGenConfig {
         f.to_string()
     }
 }
+
+struct Validator {
+    mode: Mode,
+}
+
+impl Visit for Validator {
+    fn visit_decorator(&mut self, n: &Decorator) {
+        HANDLER.with(|handler| {
+            handler.span_err(n.span, "Decorators are not supported");
+        });
+    }
+
+    fn visit_ts_enum_decl(&mut self, e: &TsEnumDecl) {
+        if matches!(self.mode, Mode::StripOnly) {
+            HANDLER.with(|handler| {
+                handler.span_err(
+                    e.span,
+                    "TypeScript enum is not supported in strip-only mode",
+                );
+            });
+            return;
+        }
+
+        e.visit_children_with(self);
+    }
+
+    fn visit_ts_param_prop_param(&mut self, n: &TsParamPropParam) {
+        if matches!(self.mode, Mode::StripOnly) {
+            HANDLER.with(|handler| {
+                handler.span_err(
+                    n.span(),
+                    "TypeScript parameter property is not supported in strip-only mode",
+                );
+            });
+            return;
+        }
+
+        n.visit_children_with(self);
+    }
+}

yarn.lock

@@ -6327,7 +6327,7 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "binding_typescript_wasm-2142ce@workspace:bindings/binding_typescript_wasm"
   dependencies:
-    jest: "npm:^25.1.0"
+    jest: "npm:^29.7.0"
   languageName: unknown
   linkType: soft