Number.round
round($numDecDigits=0, $options={}) -> number
Description
Round to the specified number of digits after the decimal point.
By default, half fractions are rounded up. (e.g. 1.5 = 2, -1.5 = -2)
$num = 3.2 $num.round() //= 3 $num = 3.5 $num.round() //= 4 $num = 3.8 $num.round() //= 4 $num = 1.2538 $num.round(2) //= 1.25 $num = 1.025 $num.round(2) //= 1.03
If $numDecimalDigits is negative, it rounds to digits left of the decimal point.
$num = 1025 $num.round(-1) //= 1030
Half Option
The half option sets what direction the number is rounded to when it is at exactly half (e.g. 0.5).
| Option | Description |
|---|---|
up |
Round up. (toward positive infinity) (default) |
down |
Round down. (toward negative infinity) |
even |
Round to the nearest even number. |
odd |
Round to the nearest odd number. |
TipIf you want to minimize statistical bias, we recommend
even (also known as statitician’s rounding).
$num = 3.5
$num.round(0, { half: 'up' }) //= 4
$num.round(0, { half: 'down' }) //= 3
$num.round(0, { half: 'odd' }) //= 3
$num.round(0, { half: 'even' }) //= 4
$num = -3.5
$num.round(0, { half: 'up' }) //= -3
$num.round(0, { half: 'down' }) //= -4
$num.round(0, { half: 'odd' }) //= -3
$num.round(0, { half: 'even' }) //= -4
Comparison of Rounding Methods
| Method | Description | Example |
|---|---|---|
| floor | Round down (toward negative infinity) | 4.7 → 4 |
| ceiling | Round up (toward positive infinity) | 2.3 → 3 |
| toInt | Drop all digits after the decimal point | 7.33 → 7 |
| round | Round to a given precision | 6.56 → 6.5 |