字符串操作javascript

Question

我正试图弄清楚如何像这样操作字符串：

string abc = "<p> Hello world <em> How are you? </em> abc <em> You there </em> </p>"

进入

string def = "<p> Hello world </> <em> How are you? </> <p> abc </> <em> You there </>" 

解释：对于每个标记，结束标记都将是</> this，我不允许像在普通HTML中那样使用嵌套标记。这就是为什么我的字符串def在每个打开标记之后都有</>的原因。

<p> hello world </> (tag closed) <em> how are you? </> (em tag closed) <p> abc </> (p tag closed) <em> You there </> (em tag closed)

我尝试在regex上使用exec来查找HTML结束标记，并用<>。它起了作用，但不幸的是，我不知道如何使用打开的标签。

我还尝试使用空格"拆分字符串并在数组中循环。但运气不好。

有人能引导我通过这个吗？

Answer 1

在这种情况下使用regex会非常困难，我们可以将数组拆分到" "上，然后简单地在其上循环，并决定字符串和标记的当前状态。

function changeHTMLEndTags(html_string = "") {
    // adding a space before '<' and after '>'
    html_string = html_string.replace(/(<)/g, ' <').replace(/(>)/g, '> ');
    // removing multiple spaces introduced due to above operation
    // and triming the start and end of the string
    html_string = html_string.replace(/ss+/g, ' ').trim();
    html_string_words = html_string.split(" ");
    
    final_html_string = "";
    
    last_opening_tag = null;
    
    for(i = 0; i < html_string_words.length; ++i) {
        
        current_word = html_string_words[i];
        
        // if the current_word is an opening tag
        if (current_word.match(/<w+>/)) {
            if (last_opening_tag === null) {
                final_html_string += current_word + " ";
                last_opening_tag = current_word;
            }
            else {
                final_html_string += "</>" + " " + current_word + " ";
                last_opening_tag = current_word;
            }
        }
        
        // if the current_word is a closing tag
        else if (current_word.match(/</w+>/)) {
            if (last_opening_tag !== null) {
                final_html_string += "</>" + " ";
                last_opening_tag = null;
            }
            else {
                // do nothing with the current_word,
                // let it get swallowed, we want to drop the dangling closing tags
            }
        }
        
        // else the current_word is a normal word
        else {
            if (last_opening_tag !== null) {
                final_html_string += current_word + " ";
            }
            else {
                // I took assumption here, 
                // that if we don't have any opening tag, we will use `<p>`
                final_html_string += "<p>" + " " + current_word + " ";
                last_opening_tag = "<p>";
            }
        }
    }
    
    return final_html_string.trim();
}
abc = "<p> Hello world <em> How are you? </em> abc <em> You there </em> </p>";
console.log(changeHTMLEndTags(abc));
abc = "<p> Hello world<em> How are you? </em> abc <em> You there </em> </p>";
console.log(changeHTMLEndTags(abc));

Answer 2

可能有一种更理想的方法可以做到这一点，但它可以用</>替换</em>和</p>，这似乎是您的目标(尽管您的问题和示例输出不一致(。

let string = "<p> Hello world <em> How are you? </em> abc <em> You there </em> </p>";
let def = string.replace(/</(em|p)>/g, "</>");
console.log(def);