JavaScript字符串Format

String.prototype.format = function () {
    if (arguments.length === 0) return this;
    var result = this;
    if (arguments.length === 1 && typeof arguments[0] === 'object') {
        for (var key in arguments[0]) {
            if (arguments[0][key] === undefined) continue;
            result = result.replace(new RegExp("({" + key + "})", "g"), arguments[0][key]);
        }
    } else {
        for (var i = 0; i < arguments.length; i++) {
            if (arguments[i] === undefined) continue;
            result = result.replace(new RegExp("({[" + i + "]})", "g"), arguments[i]);
        }
    }
    return result.toString();
}

'Welcome to {city}! My name is {name}.'.format({ city: '阜宁', name: '恋禾梦颖' });
'Total num is {0},total price is ${1}'.format(2, 10);