Iterating with for... in loop in JavaScript

Question

I have an empty array called objToArray. I'm trying to use a for-in-loop to fill the array with all of the numbers from a hash checkObj object, if the keys have a value greater than or equal to 2.

const checkObj = {
  oddNum: 1,
  evenNum: 2,
  foundNum: 5,
  randomNum: 18
};

const objToArray = [];

for (let values in checkObj) {
  if (Object.values(checkObj) >=2 ) {
    objToArray.push(checkObj.values())
    }
}

console.log(objToArray);

So far, I get objToArray as an empty array even though it should contain three elements and should equal [2, 5, 18].

Replace Object.values(checkObj) >=2 with checkObj[values] >= 2 and objToArray.push(checkObj.values()) with objToArray.push(checkObj[values]). — Karan
– Karan, Commented Jul 1, 2020 at 7:38
This works great. So basically, checkObj[values] is equivalent to the value in the hash object? — Codestudio
– Codestudio, Commented Jul 1, 2020 at 7:52
Yes, in your checkObj you can access oddNum property value with checkObj.oddNum or checkObj["oddNum"] or for let key = "oddNum"; checkObj[key] will return same value. — Karan
– Karan, Commented Jul 1, 2020 at 7:58

Karan · Accepted Answer · 2020-07-01 07:43:18Z

5

Try with Object.values(checkObj).filter(x => x >= 2);.

Get array of all values with Object.values(checkObj).
Filter array and get value >= 2 with .filter(x => x >= 2).

If you want to use for ... in loop then it iterates over key so you can get value with obj[key]. As you have declared for (let values in checkObj) values object will hold key of checkObj. So you can access value with checkObj[values].

Check output below.

const checkObj = {
  oddNum: 1,
  evenNum: 2,
  foundNum: 5,
  randomNum: 18
};

// Approach 1
let result = Object.values(checkObj).filter(x => x >= 2);
console.log(result);

// Approach 2
const objToArray = [];
for (let values in checkObj) {
  if (checkObj[values] >= 2) {
    objToArray.push(checkObj[values]);
  }
}
console.log(objToArray);

edited Jul 1, 2020 at 7:43

answered Jul 1, 2020 at 7:34

Karan

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Comments

Nithish · Accepted Answer · 2020-07-01 07:40:14Z

1

Is this you wanted?

The for...in statement iterates over all enumerable properties of an object that are keyed, it should be key rather than values.

const checkObj = {
  oddNum: 1,
  evenNum: 2,
  foundNum: 5,
  randomNum: 18
};

const objToArray = [];

for (let key in checkObj) {
  if (checkObj[key] >= 2) {
    objToArray.push(checkObj[key])
  }
}

console.log(objToArray)

edited Jul 1, 2020 at 7:40

Nithish

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answered Jul 1, 2020 at 7:34

huan feng

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Comments

Shahnawaz Hossan · Accepted Answer · 2020-07-01 07:52:59Z

1

Try this:

const checkObj = {
    oddNum: 1,
    evenNum: 2,
    foundNum: 5,
    randomNum: 18
};
    
const objToArray = [];

for (let [key, value] of Object.entries(checkObj)) {
    // console.log(`${key}: ${value}`);
    if(value>=2){
        objToArray.push(value);
    }
}

console.log(objToArray);

edited Jul 1, 2020 at 7:52

answered Jul 1, 2020 at 7:39

Shahnawaz Hossan

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1 Comment

Karan Over a year ago

As you are already iterating over key of checkObj you don't need to check if (checkObj.hasOwnProperty(property)) {, it will always true.

Bhuwan Pandey · Accepted Answer · 2020-07-01 08:02:08Z

1

Try this

const checkObj = {
  oddNum: 1,
  evenNum: 2,
  foundNum: 5,
  randomNum: 18
};

let objToArray = [];
objToArray = Object.values(checkObj).filter(elem => elem >= 2);
console.log(objToArray);

edited Jul 1, 2020 at 8:02

answered Jul 1, 2020 at 7:40

Bhuwan Pandey

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2 Comments

viam0Zah Over a year ago

Besides showing a working solution to the problem, it's worth explaining what was incorrect in the OP's proposal so that they can learn from it.

Bhuwan Pandey Over a year ago

@viam0Zah Thank You, surely I'll keep that practice in future

Ali Maher · Accepted Answer · 2020-07-01 07:43:32Z

0

try this: I hope you got it ..

let checkObj = {
  oddNum: 1,
  evenNum: 2,
  foundNum: 5,
  randomNum: 18
};

let objToArray = [];

for (let values of Object.values(checkObj)) {
  console.log(values);
  if (values >=2 ) {
    objToArray.push(values)
    }
}

answered Jul 1, 2020 at 7:43

Ali Maher

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Comments

Cedervall · Accepted Answer · 2020-07-01 09:12:35Z

0

const checkObj = {
  oddNum: 1,
  evenNum: 2,
  foundNum: 5,
  randomNum: 18
};

const objToArray = []; 

//changing the loop into a foreach loop that iterates over the keys
Object.keys(checkObj).forEach((key => {
  if (checkObj[key]) {
    objToArray.push(checkObj[key])
  }
}))

edited Jul 1, 2020 at 9:12

answered Jul 1, 2020 at 7:38

Cedervall

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1 Comment

Cedervall Over a year ago

ah right, that's correct, didn't think it through. Editing.

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