How can I check if a JSON is empty in NodeJS?

user_798491 0
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I have a function that checks to see whether or not a request has any queries, and does different actions based off that. Currently, I have if(query) do this else something else. However, it seems that when there is no query data, I end up with a {} JSON object. As such, I need to replace if(query) with if(query.isEmpty()) or something of that sort. Can anybody explain how I could go about doing this in NodeJS? Does the V8 JSON object have any functionality of this sort?

v8 node.js json javascript
6 Answers
Object.keys(myObj).length === 0;

As there is need to just check if Object is empty it will be better to directly call a native method Object.keys(myObj).length which returns the array of keys by internally iterating with for..in loop.As Object.hasOwnProperty returns a boolean result based on the property present in an object which itself iterates with for..in loop and will have time complexity O(N2).

On the other hand calling a UDF which itself has above two implementations or other will work fine for small object but will block the code which will have severe impact on overall perormance if Object size is large unless nothing else is waiting in the event loop.

user_49600390

My solution:

let isEmpty = (val) => {
    let typeOfVal = typeof val;
    switch(typeOfVal){
        case 'object':
            return (val.length == 0) || !Object.keys(val).length;
            break;
        case 'string':
            let str = val.trim();
            return str == '' || str == undefined;
            break;
        case 'number':
            return val == '';
            break;
        default:
            return val == '' || val == undefined;
    }
};
console.log(isEmpty([1,2,4,5])); // false
console.log(isEmpty({id: 1, name: "Trung",age: 29})); // false
console.log(isEmpty('TrunvNV')); // false
console.log(isEmpty(8)); // false
console.log(isEmpty('')); // true
console.log(isEmpty('   ')); // true
console.log(isEmpty([])); // true
console.log(isEmpty({})); // true
user_53617960 
const isEmpty = (value) => (
    value === undefined ||
    value === null ||
    (typeof value === 'object' && Object.keys(value).length === 0) ||
    (typeof value === 'string' && value.trim().length === 0)
  )

module.exports = isEmpty;
user_78916730
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