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1-js/4-object-basics/03-object-methods/9-string-new-property/solution.md

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+
+Try running it:
+
+```js run
+let str = "Hello";
+
+str.test = 5; // (*)
+
+alert(str.test); 
+```
+
+There may be two kinds of result:
+1. `undefined`
+2. An error.
+
+Why? Let's replay what's happening at line `(*)`:
+
+1. When a property of `str` is accessed, a "wrapper object" is created.
+2. The operation with the property is carried out on it. So, the object gets the `test` property.
+3. The operation finishes and the "wrapper object" disappears.
+
+So, on the last line, `str` has no trace of the property. A new wrapper object for every object operation on a string.
+
+Some browsers though may decide to further limit the programmer and disallow to assign properties to primitives at all. That's why in practice we can also see errors at line `(*)`. It's a little bit farther from the specification though.
+
+**This example clearly shows that primitives are not objects.**
+
+They just can not store data. 
+
+All property/method operations are performed with the help of temporary objects.
+

1-js/4-object-basics/03-object-methods/9-string-new-property/task.md

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+importance: 5
+
+---
+
+# Can I add a string property?
+
+
+Consider the following code:
+
+```js
+let str = "Hello";
+
+str.test = 5;
+
+alert(str.test);
+```
+
+How do you think, will it work? What will be shown?