round(num, decimalPlaces) {
    const p = Math.pow(10, decimalPlaces || 0);
    const n = num * p * (1 + Number.EPSILON);
    return Math.round(n) / p;
  }
Fast but accurate number rounding (https://stackoverflow.com/a/48764436/1309986 solution 2)
Half away from zero method (AKA "commercial" rounding), most common type
@param {number} num The number to be rounded
@param {number} decimalPlaces Number of DP's to round to
@returns {number} Rounded number