tocbot/src/utils/make-ids.js

Generate a table of contents based on the heading structure of a html document.

/* eslint no-var: off */

function makeIds() {
  // eslint-disable-line
  var content = document.querySelector(".js-toc-content")
  var headings = content.querySelectorAll("h1, h2, h3, h4, h5, h6, h7")
  var headingMap = {}

  Array.prototype.forEach.call(headings, function (heading) {
    var id = heading.id
      ? heading.id
      : heading.innerText
          .trim()
          .toLowerCase()
          .replace(/\s+/g, "-")
          .replace(/[^a-z0-9-]/g, "")
    headingMap[id] = !isNaN(headingMap[id]) ? ++headingMap[id] : 0
    if (headingMap[id]) {
      heading.id = id + "-" + headingMap[id]
    } else {
      heading.id = id
    }
  })
}