jeena/en.javascript.info
1
0
Fork 0
Code Issues Pull requests Projects Packages Wiki Activity Actions

minor

Browse source
This commit is contained in:
Ilya Kantor 2019-06-18 19:44:34 +03:00
parent 9b95b5ee0e
commit 061ff30189
4 changed files with 42 additions and 33 deletions
Download patch file Download diff file Expand all files Collapse all files

12
1-js/07-object-properties/02-property-accessors/article.md
View file

@ -3,7 +3,7 @@
There are two kinds of properties.
The first kind is *data properties*. We already know how to work with them. Actually, all properties that we've been using till now were data properties.
The first kind is *data properties*. We already know how to work with them. All properties that we've been using till now were data properties.
The second type of properties is something new. It's *accessor properties*. They are essentially functions that work on getting and setting a value, but look like regular properties to an external code.
@ -82,7 +82,7 @@ alert(user.name); // Alice
alert(user.surname); // Cooper
```
Now we have a "virtual" property. It is readable and writable, but in fact does not exist.
As the result, we have a "virtual" property `fullName`. It is readable and writable, but in fact does not exist.
```smart header="Accessor properties are only accessible with get/set"
Once a property is defined with `get prop()` or `set prop()`, it's an accessor property, not a data property any more.
@ -181,9 +181,9 @@ Technically, the external code may still access the name directly by using `user
## Using for compatibility
One of the great ideas behind getters and setters -- they allow to take control over a "normal" data property and tweak it at any moment.
One of the great ideas behind getters and setters -- they allow to take control over a "regular" data property at any moment by replacing it with getter and setter and tweak its behavior.
For instance, we started implementing user objects using data properties `name` and `age`:
Let's say we started implementing user objects using data properties `name` and `age`:
```js
function User(name, age) {
@ -209,9 +209,9 @@ let john = new User("John", new Date(1992, 6, 1));
Now what to do with the old code that still uses `age` property?
We can try to find all such places and fix them, but that takes time and can be hard to do if that code is written by other people. And besides, `age` is a nice thing to have in `user`, right? In some places it's just what we want.
We can try to find all such places and fix them, but that takes time and can be hard to do if that code is written/used by many other people. And besides, `age` is a nice thing to have in `user`, right? In some places it's just what we want.
Adding a getter for `age` mitigates the problem:
Adding a getter for `age` solves the problem:
```js run no-beautify
function User(name, birthday) {