add class-method-parameter-decorators

experimental/class-method-parameter-decorators.md

@@ -0,0 +1,32 @@
+# [Decorators for Class Method and Constructor Parameters][proposal-class-method-parameter-decorators]
+
+## Decorator
+
+```js
+interface Decorator <: Node {
+    type: "Decorator";
+    expression: Expression;
+}
+```
+
+## FunctionExpression
+
+```js
+extend interface FunctionExpression {
+    params: [ Pattern | Parameter ];
+}
+```
+
+If `params` contains a `Parameter` node, its parent must be a `MethodDefinition`.
+
+## Parameter
+
+```js
+interface Parameter <: Node {
+    type: "Parameter";
+    parameter: Pattern;
+    decorators: [ Decorator ];
+}
+```
+
+[proposal-class-method-parameter-decorators]: https://github.com/tc39/proposal-class-method-parameter-decorators