Custom binding for displaying money values

numericText.js

// binding for displaying money values
ko.bindingHandlers.numericText = {
    update: function (element, valueAccessor, allBindingsAccessor) {
      var value = ko.utils.unwrapObservable(valueAccessor());
        var precision = ko.utils.unwrapObservable(allBindingsAccessor().precision) ||
            ko.bindingHandlers.numericText.defaultPrecision;
        if (value === undefined || value === null) {
            return;         
        }
        var formattedValue = Number(value).toFixed(precision);
        ko.bindingHandlers.text.update(element, function() {
             return "$" + formattedValue;
        });
    },
    // Default of 2 decimal places**
    defaultPrecision: 2
};