javascript String.length 返回错误的字符数

Question

我今天遇到了一个奇怪的 JavaScript 行为，这可能是由于某些字符编码问题造成的。 length 函数为明显相同的字符串返回两个不同的字符数。在一种情况下，字符串是从数据库值复制粘贴的，在第二种情况下，我用键盘手动写入字符。我确信这与 UTF 相关，但我不知道如何获得“正确”的字符数。有没有办法知道有问题的字符串采用哪种编码并以某种方式“修复”它？有没有办法强制我的应用程序中的每个字符串都为 UTF-8 ？某处是否有隐藏 Angular 色？

感谢您的帮助

var utils = {

/**
 * cleans up our url before db insertion
 *
 * @param url
 * @returns {String} the cleaned url
 */
cleanUrl : function(url){
    url = url.trim().toLowerCase();
    if(url.includes('?'))return url;

    var lastChar = url.charAt(url.length-1);
    console.log('lastchar = ' + lastChar);
    if(lastChar == '/'){
        url=url.substring(0, url.length-1);
    }
    return url;
},

doTest : function(){
    var url = "https://bitcointalk.org/‎"; //this string was taken from DB
    console.log('url length ' + url.length);
    console.log('url length ' + url.trim().length);
    var cleaned = this.cleanUrl(url);
    console.log('cleaned length ' + cleaned.length);
    console.log('cleaned ' + cleaned);


    console.log('------------------------------');

    var url2 = "https://bitcointalk.org/";  //this string was manually written
    console.log('url2 length ' + url2.length);
    console.log('url2 length ' + url2.trim().length);

    var cleaned2 = this.cleanUrl(url2);
    console.log('cleaned2 length ' + cleaned2.length);
    console.log('cleaned2 ' + cleaned2);

}
 };

   utils.doTest()

这是输出:

url length 25
url length 25
lastchar = ‎
cleaned length 25
cleaned https://bitcointalk.org/‎
------------------------------
url2 length 24
url2 length 24
lastchar = /
cleaned2 length 23
cleaned2 https://bitcointalk.org

Answer 1

你说得对!如果您将两个字符串复制出来并在浏览器控制台中尝试，您可以看到数据库中编码的 secret 字符。