CODEWITHSUNDEEP
javascript
Vinfoster0701
Vinfoster0701

Reputation: 325

Javascript round decimal numbers

junior programmer here. I am currently working on rounding number function

so, at first, there would be a price for each item. and then there is an extra percentage button to increase the item price based on the value inserted.

So let's say item A's price is $1, then I insert value 25% into the percentage. it will give me 1.33. How to write a function that will return 1.35 instead of 1.33?

Another example, $2.67 becomes $2.70, $12.34 becomes $12.35

here is my code 

var price      = parseFloat(items.price); //1
var percentage = parseFloat(vm.data.percentage); //25%
added_price    = parseFloat(price) / (parseFloat(100) - parseFloat(percentage)) * 100; //formula
items.price    = parseFloat(added_price).toFixed(vm.data.decimal); //the result = 1.33

Can somebody help me please?? thank you :)

Upvotes: 1

Views: 123

Answers (1)

Praveen Kumar Purushothaman
Praveen Kumar Purushothaman

Reputation: 167250

Steps to do this "custom" rounding off.

  1. Multiply by 2, so that you get the nearest 0.5.
  2. Multiply by 10, so that you get it to round off.
  3. Round / Ceil the number off.
  4. Undo the multiplication by dividing it by 20.
  5. Output verified. :)

Multiply by 2 and round it off. And FYI, it would be 2.65 and not 2.70. You need to use Math.ceil() and not round.

var p1 = 2.67;
var p2 = 12.34;

function round_to_custom(num) {
  num *= 20;
  num = Math.round(num);
  num /= 20;
  return num;
}

console.log(round_to_custom(p1));
console.log(round_to_custom(p2));

Using ceil (for getting more $$$ from customers):

var p1 = 2.67;
var p2 = 12.34;

function round_to_custom(num) {
  num *= 20;
  num = Math.ceil(num);
  num /= 20;
  return num;
}

console.log(round_to_custom(p1));
console.log(round_to_custom(p2));

Upvotes: 1

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