json 语法_JSON的基本语法

json 语法

JSON which stands for JavaScript Object Notation is a lightweight readable data format that is structurally similar to a JavaScript object much like its name suggests.

代表JavaScript Object Notation的 JSON是一种轻量级的可读数据格式，其结构类似于JavaScript对象，就象其名称所暗示的那样。

It consists of two primary parts- keys and values which together combine to give it the form of the structure that we see. In this article, we'll explore some JSON syntax,

它由两个主要部分-键和值组成，它们结合在一起形成了我们看到的结构形式。在本文中，我们将探讨一些JSON语法 ，

Key: It is a string enclosed in quotes.

关键字 ：这是一个用引号引起来的字符串。

Value: It can be a string, number, boolean expression, array, object, etc and is also enclosed in quotes if it's a string.

值：它可以是字符串，数字，布尔表达式，数组，对象等，如果是字符串，也可以用引号引起来。

The key-value, when come in together separated by a colon, forms a key-value pair that essentially contains the data inside it. Every key-value pair is separated by a comma, much like in a normal JavaScript Object. The object is enclosed within curly braces.

键值以冒号分隔在一起时，会形成一个键值对，该键值对实际上包含其中的数据。每个键值对都以逗号分隔，就像在普通JavaScript对象中一样。该对象括在花括号内。

{
"userId": 1,
"id": 1,
"title": "delectus aut autem",
"completed": false
}

Above is an example of some JSON data. You can see how all the rules are being followed above? The file extension for a file storing key-value JSON pairs is '.json' and it has a mime type of 'application/json'.

上面是一些JSON数据的示例。您可以看到上面如何遵循所有规则？存储键值JSON对的文件的文件扩展名是'.json' ，并且具有mime类型'application / json' 。

You may say that JSON has borrowed or taken JavaScript syntax and it is very true but only to a certain extent. Since it's syntax is highly similar to that of a simple Javascript object people tend to confuse JSON as exactly like a JavaScript object. However, to break your bubble let me point out some differences, you can access a JavaScript object directly but not a JSON.

您可能会说JSON已经借用或采用了JavaScript语法，这是非常正确的，但只是在一定程度上。由于其语法与简单的Javascript对象的语法高度相似，因此人们倾向于像JSON对象一样混淆JSON。但是，为打破泡沫，让我指出一些区别，您可以直接访问JavaScript对象，但不能访问JSON。

var obj={
name: 'John',
type:'wwe'
}
Obj;
Obj["name"];

Output

输出量

{name: "John", type: "wwe"}
"John"

We can't do something that we did above with JSON. Also under the key-value pairs, a typical JavaScript object can have methods as properties or the value whereas the value corresponding to a key in JSON can never be a function.

我们无法使用JSON做上面的事情。同样在键值对下，典型JavaScript对象可以将方法用作属性或值，而与JSON中的键对应的值永远不能是函数。

var pokemon={
name: 'Squirtle',
type: 'Water',
HP:   100,
speak: function(){
console.log(this.name+' says hi!');
}
}
undefined
pokemon.speak();

Output

输出量

Squirtle says hi!

Also, some syntax difference is there like in a JSON the key is always enclosed inside quotes unlike in a JavaScript object where the quotes enclose a key only if deemed necessary. We can say the syntax that JSON carries is essentially a subset of the syntax of a JavaScript Object, with some additions to it.

而且，在语法上存在一些差异，例如在JSON中，密钥始终被括在引号内，这与JavaScript对象不同，在JavaScript对象中，引号仅在认为必要时才包含密钥。我们可以说JSON所承载的语法本质上是JavaScript对象语法的子集，并且有一些补充。