JS Library

String.format = function () {
    var formattedString = arguments[0];

    for (var index = 0; index < arguments.length - 1; index++) {
        var regex = new RegExp("\\{" + index + "\\}", "gm");
        formattedString = formattedString.replace(regex, arguments[index + 1]);
    }

    return formattedString;
};

var validateNumber = function (input) {
    var number = new Object();
    number.error = false;

    // In these two cases parseFloat returns MAX_INT and MIN_INT respectively, which is not expected behaviour.
    if (input != "9007199254740993" && input != "-9007199254740993") {
        number.value = parseFloat(input);

        if (isNaN(number.value)) {
            number.error = true;
            number.message = "\x27" + input + "\x27 is not a number.";
        }
    }
    else {
        number.value = input;
        number.error = true;
        number.message = input + " cannot be represented exactly with double- precision arithmetic.";
    }

    return number;
};

var validateInteger = function (input) {
    var number = validateNumber(input);

    if (!number.error) {
        if (number.value - Math.floor(number.value) != 0) {
            number.error = true;
            number.message = input + " is not an integer.";
        }
        else if (number.value > Number.MAX_INT || number.value < Number.MIN_INT) {
            number.error = true;
            number.message = String.format("Integer overflow. Integers must lie in the range [{0}, {1}].", Number.MIN_INT, Number.MAX_INT);
        }
    }

    return number;
};

// Rounds input to decimals decimal places. The built- in function only rounds integers and the function
// for fixed decimal places always puts zeroes at the end of the number to fill up to the fixed position.
// This version works much like the string format #.### where numbers are shown without the zeroes at the end
var round = function (input, decimals) {
    // Constants
    var MIN_DECIMAL_PLACES = 0;
    var MAX_DECIMAL_PLACES = 308;

    var number = new Object();
    number.value = input;
    number.error = false;

    if (decimals < MIN_DECIMAL_PLACES || decimals > MAX_DECIMAL_PLACES) {
        number.error = true;
        number.message = String.format("Cannot round to {0} decimal places. Restrictions are [{1}, {2}].", decimals, MIN_DECIMAL_PLACES, MAX_DECIMAL_PLACES);
    }
    else {
        var power = 1;
        for (var iterations = 0; iterations < decimals; iterations++) {
            power *= 10;
        }

        if (number.value * power >= Number.MAX_VALUE) {
            number.error = true;
            number.message = "Overflow. Choose a lower value for decimal places.";
        }
        else {
            number.value = Math.round(number.value * power) / power;
        }
    }

    return number;
};

/*var clearScreen = function () {
    document.body.innerHTML = String.empty;
}*/

// Useful constants that should have been built- in
String.empty = "";
Number.MAX_INT = Math.pow(2, 53);
Number.MIN_INT = -Number.MAX_INT;