Merge pull request #2926 from apoorvachikara/master

Update article.md
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Ilya Kantor 2022-04-14 06:35:03 +03:00 committed by GitHub
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@ -40,11 +40,11 @@ In the `user` object, there are two properties:
1. The first property has the name `"name"` and the value `"John"`.
2. The second one has the name `"age"` and the value `30`.
The resulting `user` object can be imagined as a cabinet with two signed files labeled "name" and "age".
The resulting `user` object can be imagined as a cabinet with two signed files labelled "name" and "age".
![user object](object-user.svg)
We can add, remove and read files from it any time.
We can add, remove and read files from it at any time.
Property values are accessible using the dot notation:
@ -62,7 +62,7 @@ user.isAdmin = true;
![user object 2](object-user-isadmin.svg)
To remove a property, we can use `delete` operator:
To remove a property, we can use the `delete` operator:
```js
delete user.age;
@ -120,7 +120,7 @@ alert(user["likes birds"]); // true
delete user["likes birds"];
```
Now everything is fine. Please note that the string inside the brackets is properly quoted (any type of quotes will do).
Now everything is fine. Please note that the string inside the brackets is properly quoted (any type of quote will do).
Square brackets also provide a way to obtain the property name as the result of any expression -- as opposed to a literal string -- like from a variable as follows:
@ -201,13 +201,13 @@ let bag = {
};
```
Square brackets are much more powerful than the dot notation. They allow any property names and variables. But they are also more cumbersome to write.
Square brackets are much more powerful than dot notation. They allow any property names and variables. But they are also more cumbersome to write.
So most of the time, when property names are known and simple, the dot is used. And if we need something more complex, then we switch to square brackets.
## Property value shorthand
In real code we often use existing variables as values for property names.
In real code, we often use existing variables as values for property names.
For instance:
@ -252,7 +252,7 @@ let user = {
## Property names limitations
As we already know, a variable cannot have a name equal to one of language-reserved words like "for", "let", "return" etc.
As we already know, a variable cannot have a name equal to one of the language-reserved words like "for", "let", "return" etc.
But for an object property, there's no such restriction:
@ -325,7 +325,7 @@ alert( "blabla" in user ); // false, user.blabla doesn't exist
Please note that on the left side of `in` there must be a *property name*. That's usually a quoted string.
If we omit quotes, that means a variable, it should contain the actual name to be tested. For instance:
If we omit quotes, that means a variable should contain the actual name to be tested. For instance:
```js run
let user = { age: 30 };
@ -412,7 +412,7 @@ for (let code in codes) {
*/!*
```
The object may be used to suggest a list of options to the user. If we're making a site mainly for German audience then we probably want `49` to be the first.
The object may be used to suggest a list of options to the user. If we're making a site mainly for a German audience then we probably want `49` to be the first.
But if we run the code, we see a totally different picture:
@ -481,7 +481,7 @@ They store properties (key-value pairs), where:
To access a property, we can use:
- The dot notation: `obj.property`.
- Square brackets notation `obj["property"]`. Square brackets allow to take the key from a variable, like `obj[varWithKey]`.
- Square brackets notation `obj["property"]`. Square brackets allow taking the key from a variable, like `obj[varWithKey]`.
Additional operators:
- To delete a property: `delete obj.prop`.