How to check if a JSON object is empty using Node.js

When using Node.js to process JSON data, you often need to check whether the JSON object is empty. In this article, we will learn how to check if a JSON object is empty using Node.js.

First, let us define an empty JSON object:

var emptyJSON = {};

In this empty JSON object, we have nothing defined, that is, there is only an empty JSON object. Now let's see how to check if it is empty.

Checking empty JSON objects

Use the JavaScript Object.keys() method to check whether the JSON object is empty. If the object is empty, the Object.keys() method will return an empty array. In the following example, we will use this method when checking for an empty JSON object:

// 定义空JSON对象
var emptyJSON = {};

// 检查空JSON对象
if(Object.keys(emptyJSON).length === 0){
    console.log('JSON对象为空');
}
else{
    console.log('JSON对象不为空');
}

In the above code, we first define an empty JSON object and then check using the Object.keys() method Got it. Since the object does not have any keys, the Object.keys() method will return an empty array. Therefore, we can check whether the JSON object is empty by checking whether the length of the returned array is 0.

Check JSON object with key-value pairs

Now, let’s add some key-value pairs to create a non-empty JSON object and test our function. In the following example, we will add three key-value pairs in the JSON object:

// 定义非空JSON对象
var nonEmptyJSON = {
    name: 'John',
    age: 21,
    country: 'USA'
};

// 检查非空JSON对象
if(Object.keys(nonEmptyJSON).length === 0){
    console.log('JSON对象为空');
}
else{
    console.log('JSON对象不为空');
}

In the above code, we define a non-empty JSON object and check it using the Object.keys() method . Since the object has three keys, the Object.keys() method will return an array containing the three keys. So when we check the returned array length, it will return a non-zero value so we know that the JSON object is not empty.

Conclusion

In this article, we learned how to check if a JSON object is empty using Node.js. We used the Object.keys() method to check whether the JSON object is empty, which determines whether the JSON object is empty by returning the length of the keys array. Using this method we can easily check if a JSON object is empty or not in Node.js.

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