how to round numbers to have decimals end in 9 in javascript code example

Example 1: math.round js 1 decimal

var number = 12.3456789;
var rounded = Math.round( number * 10 ) / 10;
// rounded is 12.3

Example 2: round to nearest decimal javascript

function round(value, precision) {
    var multiplier = Math.pow(10, precision || 0);
    return Math.round(value * multiplier) / multiplier;
}