相关疑难解决方法(0)

我在一个javascript开源项目中遇到了这段代码.

validator.isLength = function (str, min, max) 
    // match surrogate pairs in string or declare an empty array if none found in string
    var surrogatePairs = str.match(/[\uD800-\uDBFF][\uDC00-\uDFFF]/g) || [];
    // subtract the surrogate pairs string length from main string length
    var len = str.length - surrogatePairs.length;
    // now compare string length with min and max ... also make sure max is defined(in other words, max param is optional for function)
    return len >= min && (typeof max === 'undefined' || …