How do I remove an array from an object?

Question

I am attempting to write a function that iterates over a given object(obj). Each time it comes across an array within the object, it removes the array. The code seems appropriate, but please tell me what I'm missing:

function removeArrayValues(obj) {

  for (isKeyAnArray in obj) {
     if (typeof obj[isKeyAnArray] === 'array') {
       delete obj[isKeyAnArray];
    }
  }
}

var obj = {
  a: [1, 3, 4],
  b: 2,
  c: ['hi', 'there']
}

removeArrayValues(obj);
console.log(obj); // --> { b: 2 }

Answer 1

typeof returns "object" for an array. You can use Array.isArray() to check if the property is an array.

Here is the modified version of your code:

function removeArrayValues(obj) {

  for (isKeyAnArray in obj) {
     if (Array.isArray(obj[isKeyAnArray])) {
       delete obj[isKeyAnArray];
    }
  }
}

var obj = {
  a: [1, 3, 4],
  b: 2,
  c: ['hi', 'there']
}

removeArrayValues(obj);
console.log(obj);

Answer 2

check if it is an array is another way. In the included code sample 2 variations are shown.

 function removeArrayValues(obj) { for (isKeyAnArray in obj) { if (obj[isKeyAnArray] instanceof Array){ console.log("instanceof array true"); delete obj[isKeyAnArray]; } if (Array.isArray(obj[isKeyAnArray])){ console.log("isArray true"); delete obj[isKeyAnArray]; } console.log(typeof obj[isKeyAnArray]); if (typeof obj[isKeyAnArray] === 'array') { delete obj[isKeyAnArray]; } } } var obj = { a: [1, 3, 4], b: 2, c: ['hi', 'there'] } removeArrayValues(obj); console.log(obj); // --> { b: 2 } document.getElementById("exampleText").innerHTML = JSON.stringify(obj);

 <p id="exampleText"></p>

Answer 3

@Gokhan Sari 's way of doing is exactly accurate. This is more of an add-on if you wanted to go the es6 or just hipster route :D

const removeArrayValues = obj => Object.entries(obj).forEach(val => Array.isArray(val[1]) && delete obj[val[0]]);

Answer 4

Notice that this would not mutate the original object (just add as alternative answer in case it could help):

const newObj = Object.fromEntries(
  Object.entries(obj).filter(([, value]) => !Array.isArray(value))
)

console.log(newObj);