I want to return all elements in an object that has no value, empty or null.. (i.e)

 {
   firstname: "John"
   middlename: null
   lastname:  "Mayer"
   age:       ""
   gender:    "Male"
 }

I want to return the middlename and the age in the oject. Please help me. Thank you.

I want to return all elements in an object that has no value, empty or null.. (i.e)

 {
   firstname: "John"
   middlename: null
   lastname:  "Mayer"
   age:       ""
   gender:    "Male"
 }

I want to return the middlename and the age in the oject. Please help me. Thank you.

• javascript

4 Answers 4

Lets say that your request object is in a variable called obj. You can then do this:

Object.keys(obj).filter(key => obj[key] === null || obj[key] === undefined || obj[key] === "")

Object.keys will fetch all the keys of the object. You will then run a filter function over the object keys to find the required items.

Right now there are three conditions of null, undefined and empty string. You can add more as per your need.

Iterate over the entries and filter those properties whose values are null/undefined/empty string:

const obj = { firstname: "John", middlename: null, lastname: "Mayer", age: "", gender: "Male" };
const emptyishProperties = Object.entries(obj)
  .filter(([, val]) => val === null || val === undefined || val === '')
  .map(([key]) => key);
console.log(emptyishProperties);

If it's OK to also include those whose values are 0, you could simplify the filter to

.filter(([, val]) => !val)

You can convert the object into array by using Object.keys, Use filter to filter the data.

Note: this will include all falsey values. Like 0, undefined etc

let obj = {
  firstname: "John",
  middlename: null,
  lastname: "Mayer",
  age: "",
  gender: "Male"
};

let result = Object.keys(obj).filter(o => !obj[o]);
console.log(result);

If you only want to include empty string and null, you can:

let obj = {
  firstname: "John",
  middlename: null,
  lastname: "Mayer",
  age: "",
  gender: "Male"
};

let result = Object.keys(obj).filter(o => obj[o] === '' || obj[o] === null);
console.log(result);

for (var property in obj ) {
    if (obj.hasOwnProperty(property)) {
        if (!obj[property]){
            console.log(property); // This is what you're looking for, OR 'obj[property]' if you're after the values
        } 
    }
}

You can then use matching properties to create your own object. Instead of logging it to console, you could use it to meet your requirements.