(JavaScript) Compare function with == always returning false [duplicate]

Question

I have made my function that takes user input and outputs it as true if it is the same number and false if it isn't. Now my application always outputs it as false. Sorry if this is bad code, I am a noob.

I have tried to replace "== NaN" with "< 0" with no success.

function compare(a, b) {
  if (a == b) {
    var valid = true;
  } else {
    var valid = false;
  }
  return valid;
}

function test(first, second) {
  if (!isNaN(first) && !isNaN(second)) {
    alert(compare(first, second));
  } else {
    alert('TRY AGAIN');
  }
}


var firstStr = prompt('Enter first Number:');
var first = new Number(firstStr);

var secondStr = prompt('Enter second Number:');
var second = new Number(secondStr);

test(first, second);

I have not got any error messages however I got it stuck always on false, if there is anything else bad with my code please let me know.

Possible duplicate of Comparing equality of two numbers using JavaScript Number() function and new Number() vs Number() and What is the difference between “new Number(…)” and “Number(…)” in JavaScript? — adiga
– adiga, Commented May 31, 2019 at 12:04

Syed mohamed aladeen · Accepted Answer · 2019-05-31 12:06:02Z

0

You are using new Number() which will result in {} thats why it is always false

function compare(a, b) {
console.log(a,b)
    if (a == b) {
        var valid = true;
    } else {
        var valid = false;
    }
    return valid;
}

function test(first, second) {
    if(!isNaN(first) && !isNaN(second)){
        alert(compare(first, second));
    } else {
        alert('TRY AGAIN');
    }
}


var firstStr = prompt('Enter first Number:');
var first = Number(firstStr);

var secondStr = prompt('Enter second Number:');
var second = Number(secondStr);

test(first, second);

answered May 31, 2019 at 12:06

Syed mohamed aladeen

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Comments

Renan Souza · Accepted Answer · 2019-05-31 12:05:48Z

0

When you use new Number(firstStr) you're creating an object that holds more than just its value.

If you want to have just the plain integer, remove the word new and it will return only its value.

If you plan on keep the new, you need to check for a.valueOf()and b.valueOf() on your compare function.

answered May 31, 2019 at 12:05

Renan Souza

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Comments

imfsilva · Accepted Answer · 2019-05-31 12:08:39Z

0

Just remove new Number()

// same code ...

var firstStr = prompt('Enter first Number:');
var first = firstStr; // remove new Number()

var secondStr = prompt('Enter second Number:');
var second = secondStr; // remove new Number()

test(first, second);

answered May 31, 2019 at 12:08

imfsilva

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