he.ts

export function htmlDecode(str: string): string {
  return str.replace(/&(?:(\w+)|#(\d+));/g, (str, ent: string, code: string) => {
    const nCode = ent ? entities[ent] : parseInt(code);
    return isNaN(nCode) ? str : String.fromCodePoint(nCode);
  });
}

const entities: {[key: string]: number} = {
  amp: 38,
  lt: 60,
  gt: 62,
  Agrave: 192,
  Aacute: 193,
  Acirc: 194,
  Atilde: 195,
  Auml: 196,
  Aring: 197,
  AElig: 198,
  Ccedil: 199,
  Egrave: 200,
  Eacute: 201,
  Ecirc: 202,
  Euml: 203,
  Igrave: 204,
  Iacute: 205,
  Icirc: 206,
  Iuml: 207,
  ETH: 208,
  Ntilde: 209,
  Ograve: 210,
  Oacute: 211,
  Ocirc: 212,
  Otilde: 213,
  Ouml: 214,
  Oslash: 216,
  Ugrave: 217,
  Uacute: 218,
  Ucirc: 219,
  Uuml: 220,
  Yacute: 221,
  THORN: 222,
  szlig: 223,
  agrave: 224,
  aacute: 225,
  acirc: 226,
  atilde: 227,
  auml: 228,
  aring: 229,
  aelig: 230,
  ccedil: 231,
  egrave: 232,
  eacute: 233,
  ecirc: 234,
  euml: 235,
  igrave: 236,
  iacute: 237,
  icirc: 238,
  iuml: 239,
  eth: 240,
  ntilde: 241,
  ograve: 242,
  oacute: 243,
  ocirc: 244,
  otilde: 245,
  ouml: 246,
  oslash: 248,
  ugrave: 249,
  uacute: 250,
  ucirc: 251,
  uuml: 252,
  yacute: 253,
  thorn: 254,
  yuml: 255,
  nbsp: 160,
  iexcl: 161,
  cent: 162,
  pound: 163,
  curren: 164,
  yen: 165,
  brvbar: 166,
  sect: 167,
  uml: 168,
  copy: 169,
  ordf: 170,
  laquo: 171,
  not: 172,
  shy: 173,
  reg: 174,
  macr: 175,
  deg: 176,
  plusmn: 177,
  sup2: 178,
  sup3: 179,
  acute: 180,
  micro: 181,
  para: 182,
  cedil: 184,
  sup1: 185,
  ordm: 186,
  raquo: 187,
  frac14: 188,
  frac12: 189,
  frac34: 190,
  iquest: 191,
  times: 215,
  divide: 247,
  forall: 8704,
  part: 8706,
  exist: 8707,
  empty: 8709,
  nabla: 8711,
  isin: 8712,
  notin: 8713,
  ni: 8715,
  prod: 8719,
  sum: 8721,
  minus: 8722,
  lowast: 8727,
  radic: 8730,
  prop: 8733,
  infin: 8734,
  ang: 8736,
  and: 8743,
  or: 8744,
  cap: 8745,
  cup: 8746,
  int: 8747,
  there4: 8756,
  sim: 8764,
  cong: 8773,
  asymp: 8776,
  ne: 8800,
  equiv: 8801,
  le: 8804,
  ge: 8805,
  sub: 8834,
  sup: 8835,
  nsub: 8836,
  sube: 8838,
  supe: 8839,
  oplus: 8853,
  otimes: 8855,
  perp: 8869,
  sdot: 8901,
  Alpha: 913,
  Beta: 914,
  Gamma: 915,
  Delta: 916,
  Epsilon: 917,
  Zeta: 918,
  Eta: 919,
  Theta: 920,
  Iota: 921,
  Kappa: 922,
  Lambda: 923,
  Mu: 924,
  Nu: 925,
  Xi: 926,
  Omicron: 927,
  Pi: 928,
  Rho: 929,
  Sigma: 931,
  Tau: 932,
  Upsilon: 933,
  Phi: 934,
  Chi: 935,
  Psi: 936,
  Omega: 937,
  alpha: 945,
  beta: 946,
  gamma: 947,
  delta: 948,
  epsilon: 949,
  zeta: 950,
  eta: 951,
  theta: 952,
  iota: 953,
  kappa: 954,
  lambda: 955,
  mu: 956,
  nu: 957,
  xi: 958,
  omicron: 959,
  pi: 960,
  rho: 961,
  sigmaf: 962,
  sigma: 963,
  tau: 964,
  upsilon: 965,
  phi: 966,
  chi: 967,
  psi: 968,
  omega: 969,
  thetasym: 977,
  upsih: 978,
  piv: 982,
  OElig: 338,
  oelig: 339,
  Scaron: 352,
  scaron: 353,
  Yuml: 376,
  fnof: 402,
  circ: 710,
  tilde: 732,
  ensp: 8194,
  emsp: 8195,
  thinsp: 8201,
  zwnj: 8204,
  zwj: 8205,
  lrm: 8206,
  rlm: 8207,
  ndash: 8211,
  mdash: 8212,
  lsquo: 8216,
  rsquo: 8217,
  sbquo: 8218,
  ldquo: 8220,
  rdquo: 8221,
  bdquo: 8222,
  dagger: 8224,
  Dagger: 8225,
  bull: 8226,
  hellip: 8230,
  permil: 8240,
  prime: 8242,
  Prime: 8243,
  lsaquo: 8249,
  rsaquo: 8250,
  oline: 8254,
  euro: 8364,
  trade: 8482,
  larr: 8592,
  uarr: 8593,
  rarr: 8594,
  darr: 8595,
  harr: 8596,
  crarr: 8629,
  lceil: 8968,
  rceil: 8969,
  lfloor: 8970,
  rfloor: 8971,
  loz: 9674,
  spades: 9824,
  clubs: 9827,
  hearts: 9829,
  diams: 9830,
};