58 lines
1.5 KiB
Markdown
58 lines
1.5 KiB
Markdown
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---
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title: JSON Parse
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localeTitle: JSON Parse
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---
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## JSON Parse
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`JSON.parse()`方法解析字符串并构造由字符串描述的新对象。
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#### 句法：
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```javascript
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JSON.parse(text [, reviver])
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```
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##### 参数：
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`text` 要解析为JSON的字符串
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`reviver` （可选） 该函数将接收`key`和`value`作为参数。此函数可用于转换结果值。
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以下是如何使用`JSON.parse()`的示例：
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```javascript
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var data = '{"foo": "bar"}';
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console.log(data.foo); // This will print `undefined` since `data` is of type string and has no property named as `foo`
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// You can use JSON.parse to create a new JSON object from the given string
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var convertedData = JSON.parse(data);
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console.log(convertedData.foo); // This will print `bar
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```
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[Repl.it演示](https://repl.it/MwgK/0)
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这是`reviver`一个例子：
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```javascript
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var data = '{"value": 5}';
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var result = JSON.parse(data, function(key, value) {
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if (typeof value === 'number') {
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return value * 10;
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}
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return value;
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});
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// Original Data
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console.log("Original Data:", data); // This will print Original Data: {"value": 5}
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// Result after parsing
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console.log("Parsed Result: ", result); // This will print Parsed Result: { value: 50 }
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```
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在上面的示例中，所有数字值都乘以`10` - [Repl.it Demo](https://repl.it/Mwfp/0)
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#### 更多信息：
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[JSON.parse - MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse)
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