add wasm_bindgen(skip) to reference

guide/src/SUMMARY.md

@@ -75,6 +75,7 @@
       - [`constructor`](./reference/attributes/on-rust-exports/constructor.md)
       - [`js_name = Blah`](./reference/attributes/on-rust-exports/js_name.md)
       - [`readonly`](./reference/attributes/on-rust-exports/readonly.md)
+      - [`skip`](./reference/attributes/on-rust-exports/skip.md)
       - [`start`](./reference/attributes/on-rust-exports/start.md)
       - [`typescript_custom_section`](./reference/attributes/on-rust-exports/typescript_custom_section.md)
 

guide/src/reference/attributes/on-rust-exports/skip.md

@@ -0,0 +1,46 @@
+# `skip`
+
+When attached to a `pub` struct field this indicates that field will not be exposed to JavaScript,
+and neither getter nor setter will be generated in ES6 class.
+
+```rust
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub struct Foo {
+    pub bar: u32,
+
+    #[wasm_bindgen(skip)]
+    pub baz: u32,
+}
+
+#[wasm_bindgen]
+impl Foo {
+    pub fn new() -> Self {
+        Foo {
+            bar: 1,
+            baz: 2
+        }
+    }
+}
+```
+
+Here the `bar` field will be both readable and writable from JS, but the
+`baz` field will be `undefined` in JS.
+
+```js
+import('./pkg/').then(rust => {
+    let foo = rust.Foo.new();
+    
+    // bar is accessible by getter
+    console.log(foo.bar);
+    // field marked with `skip` is undefined
+    console.log(foo.baz);      
+
+    // you can shadow it
+    foo.baz = 45;       
+    // so accessing by getter will return `45`
+    // but it won't affect real value in rust memory
+    console.log(foo.baz);
+});
+```