add declare to class properties type annotations (#12257)

* add declare to class properties type annotations

* chore: use preset-flow

packages/babel-parser/src/parser/base.js

@@ -10,23 +10,23 @@ import type ProductionParameterHandler from "../util/production-parameter";
 
 export default class BaseParser {
   // Properties set by constructor in index.js
-  options: Options;
-  inModule: boolean;
-  scope: ScopeHandler<*>;
-  classScope: ClassScopeHandler;
-  prodParam: ProductionParameterHandler;
-  expressionScope: ExpressionScopeHandler;
-  plugins: PluginsMap;
-  filename: ?string;
+  declare options: Options;
+  declare inModule: boolean;
+  declare scope: ScopeHandler<*>;
+  declare classScope: ClassScopeHandler;
+  declare prodParam: ProductionParameterHandler;
+  declare expressionScope: ExpressionScopeHandler;
+  declare plugins: PluginsMap;
+  declare filename: ?string;
   sawUnambiguousESM: boolean = false;
   ambiguousScriptDifferentAst: boolean = false;
 
   // Initialized by Tokenizer
-  state: State;
+  declare state: State;
   // input and length are not in state as they are constant and we do
   // not want to ever copy them, which happens if state gets cloned
-  input: string;
-  length: number;
+  declare input: string;
+  declare length: number;
 
   hasPlugin(name: string): boolean {
     return this.plugins.has(name);