Nov 10, 2025 · Nov 13, 2025
diff --git a/1-js/05-data-types/07-map-set/article.md b/1-js/05-data-types/07-map-set/article.md

 As we can see, unlike objects, keys are not converted to strings. Any type of key is possible.

 ```smart header="`map[key]` isn't theright way to use a `Map`"
 Although`map[key]` also works, e.g. wecanset`map[key] =2`, thisis treating `map` as a plain JavaScript object, so it implies all corresponding limitations (only string/symbol keys and so on).
 ````smart header="`map[key]` isn’t thecorrect way to use a `Map`"
 Althoughyoucantechnically write`map[key] =value`, thisdoes **not** store the data inside the `Map` collection.

 So we should use `map` methods: `set`, `get` and so on.
 Instead, it simply adds a regular property to the `Map` object itself—just like with plain JavaScript objects—and the key is always converted to a string.

 For example:

 ```js run
 let map = new Map();
 map["1"] = "test"; // adds a property, not a Map entry

 alert(map.get("1")); // undefined
 alert(map["1"]);     // "test"
 ```

 To properly store and retrieve data in a `Map`, always use its methods:
 `map.set(key, value)` and `map.get(key)`.
 ````

 **Map can also use objects as keys.**

 For instance:
Original file line number	Diff line number	Diff line change
Expand Up		@@ -41,12 +41,25 @@ alert( map.size ); // 3

		As we can see, unlike objects, keys are not converted to strings. Any type of key is possible.

		```smart header="`map[key]` isn't theright way to use a `Map`"
		Although`map[key]` also works, e.g. wecanset`map[key] =2`, thisis treating `map` as a plain JavaScript object, so it implies all corresponding limitations (only string/symbol keys and so on).
		````smart header="`map[key]` isn’t thecorrect way to use a `Map`"
		Althoughyoucantechnically write`map[key] =value`, thisdoes not store the data inside the `Map` collection.

		So we should use `map` methods: `set`, `get` and so on.
		Instead, it simply adds a regular property to the `Map` object itself—just like with plain JavaScript objects—and the key is always converted to a string.

		For example:

		```js run
		let map = new Map();
		map["1"] = "test"; // adds a property, not a Map entry

		alert(map.get("1")); // undefined
		alert(map["1"]); // "test"
		```

		To properly store and retrieve data in a `Map`, always use its methods:
		`map.set(key, value)` and `map.get(key)`.
		````

		Map can also use objects as keys.

		For instance:
Expand Down