JavaScript实现文本相似度对比

function similar(s, t, f) {
  if (!s || !t) {
    return 0
  }
  if(s === t){
    return 100;
  }
  var l = s.length > t.length ? s.length : t.length
  var n = s.length
  var m = t.length
  var d = []
  f = f || 2
  var min = function (a, b, c) {
    return a < b ? (a < c ? a : c) : (b < c ? b : c)
  }
  var i, j, si, tj, cost
  if (n === 0) return m
  if (m === 0) return n
  for (i = 0; i <= n; i++) {
    d[i] = []
    d[i][0] = i
  }
  for (j = 0; j <= m; j++) {
    d[0][j] = j
  }
  for (i = 1; i <= n; i++) {
    si = s.charAt(i - 1)
    for (j = 1; j <= m; j++) {
      tj = t.charAt(j - 1)
      if (si === tj) {
        cost = 0
      } else {
        cost = 1
      }
      d[i][j] = min(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1] + cost)
    }
  }
  let res = (1 - d[n][m] / l) *100
  return res.toFixed(f)
}