Javascript toFixed function

Question

The expected result of:

(1.175).toFixed(2) = 1.18 and
(5.175).toFixed(2) = 5.18

But in JS showing:

Answer 1

Kippie your solution has problems one of them

39133.005.toFixed(2) => 39133 

var Calc = function () {
    var self = this;

this.float2Array = function(num) {
    var floatString = num.toString(),
        exp = floatString.indexOf(".") - (floatString.length - 1),
        mant = floatString.replace(".", "").split("").map(function (i) { return parseInt(i); });
    return { exp: exp, mant: mant };
};

this.round2 = function (num, dec, sep) {
    var decimal = !!dec ? dec : 2,
    separator = !!sep ? sep : '',
    r = parseFloat(num),
    exp10 = Math.pow(10, decimal);
    r = Math.round(r * exp10) / exp10;

    var rr = Number(r).toFixed(decimal).toString().split('.');

    var b = rr[0].replace(/(\d{1,3}(?=(\d{3})+(?:\.\d|\b)))/g, "\$1" + separator);
    r = (rr[1] ? b + '.' + rr[1] : b);

    return r;
};

this.toFixed10 = function (f, num) {
    var prepareInt = self.float2Array(f),
        naturalInt = prepareInt.mant,
        places = Math.abs(prepareInt.exp),
        result = prepareInt.mant.slice(),
        resultFixedLenth;

    // if number non fractional or has zero fractional part
    if (f.isInt()) {
        return f.toFixed(num);
    }
    // if the number of decimal places equals to required rounding
    if (places === num) {
        return Number(f).toString();
    }
    //if number has trailing zero (when casting to string type float 1.0050 => "1.005" => 005 <0050)
    if (places < num) {
        return Number(f).round2(num);
    }

    for (var e = naturalInt.length - (places > num ? (places - num) : 0), s = 0; e >= s; e--) {
        if (naturalInt.hasOwnProperty(e)) {
            if (naturalInt[e] > 4 && naturalInt[e - 1] < 9) {
                result[e] = 0;
                result[e - 1] = naturalInt[e - 1] + 1;
                break;
            } else if (naturalInt[e] > 4 && naturalInt[e - 1] === 9) {
                result[e] = 0;
                result[e - 1] = 0;
                result[e - 2] = naturalInt[e - 2] < 9 ? naturalInt[e - 2] + 1 : 0;
            } else if (e === 0 && naturalInt[e] === 9 && naturalInt[e + 1] === 9) {
                result[e] = 0;
                result.unshift(1);
            } else {
                break;
            }
        }
    }

    if (places - num > 0) {
        resultFixedLenth = result.slice(0, -(places - num));
    } else {
        for (var i = 0, l = num - places; i < l; i++) {
            result.push(0);
        }
        resultFixedLenth = result;
    }

    return (parseInt(resultFixedLenth.join("")) / Math.pow(10, num)).round2(num);
};
this.polyfill = function() {
    if (!Array.prototype.map) {
        Array.prototype.map = function (callback, thisArg) {
            var T, A, k;
            if (this == null) { throw new TypeError(' this is null or not defined'); }
            var O = Object(this), len = O.length >>> 0;
            if (typeof callback !== 'function') { throw new TypeError(callback + ' is not a function'); }
            if (arguments.length > 1) { T = thisArg; }

            A = new Array(len);
            k = 0;
            while (k < len) {
                var kValue, mappedValue;
                if (k in O) {
                    kValue = O[k];
                    mappedValue = callback.call(T, kValue, k, O);
                    A[k] = mappedValue;
                }
                k++;
            }
            return A;
        };
    }
};

this.init = function () {
    self.polyfill();
    Number.prototype.toFixed10 = function (decimal) {
        return calc.toFixed10(this, decimal);
    }
    Number.prototype.round2 = function (decimal) {
        return calc.round2(this, decimal);
    }
    Number.prototype.isInt = function () {
        return (Math.round(this) == this);
    }
}
}, calc = new Calc(); calc.init();

this works good)