Node.js - escape HTML special characters

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
// Note: in this snippet you can find optimal solution to escape HTML special characters.

const escapeHtml = (html) => {
    let result = '';
    let escape = '';
    let helper = 0;
    let index = 0;
    for (; index < html.length; ++index) {
        switch (html.charCodeAt(index)) {
            case 34: escape = '&#34;'; break;  //  "  // &quot;
            case 38: escape = '&#38;'; break;  //  &  // &amp;
            case 39: escape = '&#39;'; break;  //  '
            case 60: escape = '&#60;'; break;  //  <  // &lt;
            case 62: escape = '&#62;'; break;  //  >  // &gt;
            default: continue;
        }
        if (helper < index) {
            result += html.substring(helper, index);
        }
        result += escape; 
        helper = index + 1;
    }
    if (helper < index) {
        result += html.substring(helper, index);
    }
    return result;
};


// Usage example:

console.log(escapeHtml('<div class="message">Hi!</div>'));  // &#60;div class=&#34;message&#34;&#62;Hi!&#60;/div&#62;


// Output:
//
//     &#60;div class=&#34;message&#34;&#62;Hi!&#60;/div&#62;