// Utility functions

// Copy all attributes from source object to destination object.
// destination object is mutated.
function extend(destination, source) {
    destination = destination || {};
    source = source || {};

    for (var attrName in source) {
        if (source.hasOwnProperty(attrName)) {
            destination[attrName] = source[attrName];
        }
    }

    return destination;
}

// Renders templates with given variables. Variables must be surrounded with
// braces without any spaces, e.g. {variable}
// All instances of variable placeholders will be replaced with given content
// Example:
// render('Hello, {message}!', {message: 'world'})
function render(template, vars) {
    var rendered = template;

    for (var key in vars) {
        if (vars.hasOwnProperty(key)) {
            var val = vars[key];
            var regExpString = '\\{' + key + '\\}';
            var regExp = new RegExp(regExpString, 'g');

            rendered = rendered.replace(regExp, val);
        }
    }

    return rendered;
}

function isString(obj) {
    return typeof obj === 'string' || obj instanceof String;
}

function isFunction(obj) {
    return typeof obj === 'function';
}

module.exports = {
    extend: extend,
    render: render,
    isString: isString,
    isFunction: isFunction
};