Misago/frontend/src/utils/escape-html.js

const map = {
  "&": "&",
  "<": "&lt;",
  ">": "&gt;",
  '"': "&quot;",
  "'": "&#039;"
}

export default function(text) {
  return text.replace(/[&<>"']/g, function(m) {
    return map[m]
  })
}