Add Matching Multiple Values In A Switch Statement as a javascript til

javascript/matching-multiple-values-in-a-switch-statement.md

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+# Matching Multiple Values In A Switch Statement
+
+Switch statements are a handy way to execute different branches of code
+based on a value match. This is often what is used in Redux reducers when
+updating the state in response to certain actions.
+
+But what if you need multiple values to result in the same branch of
+execution without duplicating the code?
+
+The execution of a switch statement falls through, so after one match, it
+will continue to try and do subsequent matches if you don't interrupt the
+execution with a `break` or `return`. Conveniently, this solves our problem
+of matching multiple values.
+
+```javascript
+switch (action.type) {
+  case "UPDATE_NAME":
+  case "UPDATE_DURATION":
+    let newData = anotherReducer(state.data, action);
+    return { ...state, data: newData };
+  default:
+    return state;
+}
+```
+
+See the [MDN
+docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/switch)
+for more details.