Add skip_typescript attribute to prevent .d.ts emit (#2016)

* Add skip_typescript attribute to prevent .d.ts emit

* Add guide page for typescript attribute

crates/typescript-tests/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2018"
 [dependencies]
 wasm-bindgen = { path = '../..' }
 web-sys = { path = '../web-sys', features = [ 'HtmlElement', 'Node', 'Document' ] }
+js-sys = { path = '../js-sys' }
 
 [lib]
 crate-type = ['cdylib']

crates/typescript-tests/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod custom_section;
 pub mod getters_setters;
+pub mod omit_definition;
 pub mod opt_args_and_ret;
 pub mod optional_fields;
 pub mod simple_fn;

crates/typescript-tests/src/omit_definition.rs

@@ -0,0 +1,34 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen(typescript_custom_section)]
+const TYPE_GET_VALUE: &'static str =
+    "export function take_function(func: (x: number) => void): void;";
+
+#[wasm_bindgen(skip_typescript)]
+pub fn take_function(_: js_sys::Function) {}
+
+#[wasm_bindgen]
+pub struct MyExportedStruct {
+    #[wasm_bindgen(skip_typescript)]
+    pub field: bool,
+}
+
+#[wasm_bindgen]
+impl MyExportedStruct {
+    #[wasm_bindgen(skip_typescript)]
+    pub fn method(&mut self) {
+        self.field = !self.field;
+    }
+
+    #[wasm_bindgen(skip_typescript)]
+    pub fn static_func() {
+        panic!("oh no!");
+    }
+}
+
+#[wasm_bindgen(skip_typescript)]
+pub enum MyEnum {
+    One,
+    Two,
+    Three,
+}

crates/typescript-tests/src/omit_definition.ts

@@ -0,0 +1,26 @@
+import * as wbg from '../pkg/typescript_tests';
+
+wbg.take_function((value) => {
+    // `value` should be inferred as `number` because of the
+    // custom typescript section. If `typescript = false` does
+    // not prevent the generation of a signature that takes any
+    // function, then this will trigger a noImplicitAny error.
+    console.log(value);
+});
+
+declare function assert<T>(message: T): void;
+
+type EnableIfEnum = "MyEnum" extends keyof typeof wbg ? never : string;
+assert<EnableIfEnum>("`MyEnum` type should not be exported.");
+
+type EnableIfStruct = "MyStruct" extends keyof typeof wbg ? never : string;
+assert<EnableIfStruct>("`MyStruct` type should not be exported.");
+
+type EnableIfField = "field" extends keyof wbg.MyExportedStruct ? never : string;
+assert<EnableIfField>("`field` should not exist on `MyExportedStruct`.");
+
+type EnableIfMethod = "method" extends keyof wbg.MyExportedStruct ? never : string;
+assert<EnableIfMethod>("`method` should not exist on `MyExportedStruct`.");
+
+type EnableIfStaticMethod = "static_func" extends keyof typeof wbg.MyExportedStruct ? never : string;
+assert<EnableIfStaticMethod>("`static_func` should not exist on `MyExportedStruct`.");