How to use the markdown-it/lib/common/utils.isSpace function in markdown-it

// Parse link destination


var isSpace     = require('markdown-it/lib/common/utils').isSpace;
var unescapeAll = require('markdown-it/lib/common/utils').unescapeAll;


const parseLinkDestination = function (str, pos, max) {
  var code, level,
      lines = 0,
      start = pos,
      result = {
        ok: false,
        pos: 0,
        lines: 0,
        str: ''
      };

  if (str.charCodeAt(pos) === 0x3C /* < */) {
    pos++;

'use strict';

// Parse link destination


var isSpace = require('markdown-it/lib/common/utils').isSpace;
var unescapeAll = require('markdown-it/lib/common/utils').unescapeAll;

var parseLinkDestination = function parseLinkDestination(str, pos, max) {
  var code,
      level,
      lines = 0,
      start = pos,
      result = {
    ok: false,
    pos: 0,
    lines: 0,
    str: ''
  };

  if (str.charCodeAt(pos) === 0x3C /* < */) {
      pos++;