Text wrap like html

note.el

(defun define-it--wrap-string (str len)
  "Wrap the STR under the LEN."
  (let ((res-str "") (min 0) (new-len len) (added-nl-count 0))
    (while (and (< min new-len)
                (< new-len (length str)))
      (let* ((line (substring str min new-len))
             (spc-lst (split-string line " "))
             (last-elm (nth (1- (length spc-lst)) spc-lst)))
        (setq res-str
              (concat res-str
                      (substring line 0 (- len (length last-elm)))
                      "\n"))
        (setq added-nl-count (1+ added-nl-count))
        (setq min (- (length res-str) added-nl-count))
        (setq new-len (+ min len))))
    (setq res-str (concat res-str (substring str min (length str))))
    res-str))