Add more reducer patterns!

Author: RoyalIcing

lib/components_guide_web/templates/react_typescript/reducer-patterns.html.md

@@ -1,5 +1,21 @@
 # React Reducer Patterns
 
+## One-Way Flag
+
+```js
+const [isEnabled, enable] = useReducer(() => true, false);
+```
+
+[Source](https://twitter.com/markdalgleish/status/1521304112738217984)
+
+## Toggle Flag
+
+```js
+const [on, toggle] = useReducer(flag => !flag, false)
+```
+
+[Source](https://twitter.com/FernandoTheRojo/status/1521305729558274048)
+
 ## Menu
 
 ```ts

lib/components_guide_web/templates/web_standards/javascript-collections.html.md

@@ -0,0 +1,24 @@
+# JavaScript Key-Value Collections
+
+- Map
+- URLSearchParams
+- FormData
+- Object
+- WeakMap
+
+## Map
+
+- **Pro:** keys can be any JavaScript value, not just strings.
+- **Con:** homogeneous TypeScript values.
+- 💡 Clone:
+```js
+const newMap = new Map(otherMap);
+```
+
+## URLSearchParams
+
+- Spec: serializes to `application/x-www-form-urlencoded`
+
+## Objects
+
+- Keys can be strings or symbols.