// HTML (and XML) text/attribute escaping.

const HTML_ESCAPES = {
    "&":  "&",
    "<":  "&lt;",
    ">":  "&gt;",
    "\"": "&quot;",
    "'":  "&#39;"
};
const HTML_SPECIALS = /[&<>"']/g;


// value as text safe inside an element or a quoted attribute; null/undefined -> "".
const escapeHtml = (value) => {
    if (value === null || value === undefined) {
        return "";
    }
    return String(value).replace(HTML_SPECIALS, (ch) => HTML_ESCAPES[ch]);
};


module.exports = {
    escapeHtml
};