JS — Add prototyped accurate rounding to Number

Number.round.js

/**
 * Custom rounding added prototype
 * @param number The number to apply rounding to. Must be of type Number.
 * @param decimals Number of decimal points to keep. Must be in the range of 0 - 20.
 */
// Vue prototyping ES6
Vue.prototype.$roundNumber = (number, decimals) => Number(
  (`${Math.round(`${number}e${decimals}`)}e-${decimals}`),
);

// Example usage
var roundInVue = 1.005;
console.log(this.$roundNumber(roundInVue, 2));
// -> 1.01


/**
 * Custom rounding added prototype
 * @param decimals Number of decimal points to keep. Must be in the range of 0 - 20.
 */
// ES6
Number.prototype.round = (decimals) => Number((`${Math.round(`${this}e${decimals}`)}e-${decimals}`));

// ES5
Number.prototype.round = function(decimals) {
    return Number((Math.round(this + "e" + decimals)  + "e-" + decimals));
}

// Example usage
var numberToRound = 1.005;
console.log(numberToRound.round(2));
// -> 1.01

Source: https://stackoverflow.com/a/29101013/5415663
Fiddle: https://jsfiddle.net/k5tpq3pd/35/