Nodejs Utililty Methods String to Enum Convert

"use strict";
var toEnum = function (string, Type) {
    var value = parseFloat(Type[string.trim()].valueOf());
    if (isNaN(value)) {
        throw new Error("Coundn't resolve string to an Enum value.");
    return value;
};
String.prototype.toEnum = function (Type) {
...

"use strict";
var toEnumFlag = function (string, Type) {
    var keys = string.split(",");
    var intList = keys.filter(function (string) {
        return Type[string.trim()] == null ? false : true;
    }).map(function (string) {
        return Type[string.trim()];
    });
    if (intList.length === 0) {
...

Number.prototype.toEnumFlagString = function (Type) {
    var value = this.valueOf();
    var response = Object.keys(Type).filter(function (key) {
        return ((value & Type[key]) == Type[key]) && Type[key] != 0 && typeof Type[key].name === "string";
    }).map(function (key) {
        return Type[key].name || key;
    }).join(", ");
    return (response.length > 0 ? response : "None");
};
...

Number.prototype.toEnumString = function (Type) {
    var number = this.valueOf();
    var response = Object.keys(Type).filter(function (key) {
        return Type[key] != null && typeof Type[key].name === "string" && Type[key].valueOf() === number.valueOf();
    });
    var string = response[0];
    if (string == null) {
        throw new Error("Couldn't find Enum string value.");
    return string;
};