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

Question

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, if 33 is passed I should return 30.

Answer 1

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;

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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;