How to round an integer up or down to the nearest 10 using Javascript

Using Javascript, I would like to round a number passed by a user to the nearest 10. For example, if 7 is passed I should return 10,开发者_高级运维 if 33 is passed I should return 30.

Divide the number by 10, round the result and multiply it with 10 again, for example:

1. 33 / 10 = 3.3
2. 3.3 rounded = 3
3. 3 × 10 = 30

console.log(Math.round(prompt('Enter a number', 33) / 10) * 10);

Math.round(x / 10) * 10

Where i is an int.

To round down to the nearest multiple of 10 i.e.

11 becomes 10
19 becomes 10
21 becomes 20

parseInt(i / 10, 10) * 10;

To round up to the nearest multiple of 10 i.e.

11 becomes 20
19 becomes 20
21 becomes 30

parseInt(i / 10, 10) + 1 * 10;  

I needed something similar, so I wrote a function. I used the function for decimal rounding here, and since I also use it for integer rounding, I will set it as the answer here too. In this case, just pass in the number you want to round and then 10, the number you want to round to.

function roundToNearest(numToRound, numToRoundTo) {
    return Math.round(numToRound / numToRoundTo) * numToRoundTo;
}